Time-dependent nonequilibrium soft x-ray response during a spin crossover

NASA Astrophysics Data System (ADS)

van Veenendaal, Michel

2018-03-01

A theoretical framework is developed for better understanding the time-dependent soft-x-ray response of dissipative quantum many-body systems. It is shown how x-ray absorption and resonant inelastic x-ray scattering (RIXS) at transition-metal L edges can provide insight into ultrafast intersystem crossings of importance for energy conversion, ultrafast magnetism, and catalysis. The photoinduced doublet-to-quartet spin crossover on cobalt in Fe-Co Prussian blue analogs is used as a model system to demonstrate how the x-ray response is affected by the nonequilibrium dynamics on a femtosecond time scale. Changes in local spin and symmetry and the underlying mechanism are reflected in strong broadenings, a collapse of clear selection rules during the intersystem crossing, fluctuations in the isotropic branching ratio in x-ray absorption, crystal-field collapse and/or oscillations, and time-dependent anti-Stokes processes in RIXS.

X-ray induced dimerization of cinnamic acid: Time-resolved inelastic X-ray scattering study

PubMed Central

Inkinen, Juho; Niskanen, Johannes; Talka, Tuomas; Sahle, Christoph J.; Müller, Harald; Khriachtchev, Leonid; Hashemi, Javad; Akbari, Ali; Hakala, Mikko; Huotari, Simo

2015-01-01

A classic example of solid-state topochemical reactions is the ultraviolet-light induced photodimerization of α-trans-cinnamic acid (CA). Here, we report the first observation of an X-ray-induced dimerization of CA and monitor it in situ using nonresonant inelastic X-ray scattering spectroscopy (NRIXS). The time-evolution of the carbon core-electron excitation spectra shows the effects of two X-ray induced reactions: dimerization on a short time-scale and disintegration on a long time-scale. We used spectrum simulations of CA and its dimerization product, α-truxillic acid (TA), to gain insight into the dimerization effects. From the time-resolved spectra, we extracted component spectra and time-dependent weights corresponding to CA and TA. The results suggest that the X-ray induced dimerization proceeds homogeneously in contrast to the dimerization induced by ultraviolet light. We also utilized the ability of NRIXS for direct tomography with chemical-bond contrast to image the spatial progress of the reactions in the sample crystal. Our work paves the way for other time-resolved studies on chemical reactions using inelastic X-ray scattering. PMID:26568420

Resonant soft X-ray scattering for polymer materials

DOE PAGES

Liu, Feng; Brady, Michael A.; Wang, Cheng

2016-04-16

Resonant Soft X-ray Scattering (RSoXS) was developed within the last few years, and the first dedicated resonant soft X-ray scattering beamline for soft materials was constructed at the Advanced Light Source, LBNL. RSoXS combines soft X-ray spectroscopy with X-ray scattering and thus offers statistical information for 3D chemical morphology over a large length scale range from nanometers to micrometers. Using RSoXS to characterize multi-length scale soft materials with heterogeneous chemical structures, we have demonstrated that soft X-ray scattering is a unique complementary technique to conventional hard X-ray and neutron scattering. Its unique chemical sensitivity, large accessible size scale, molecular bondmore » orientation sensitivity with polarized X-rays, and high coherence have shown great potential for chemically specific structural characterization for many classes of materials.« less

High-efficiency in situ resonant inelastic x-ray scattering (iRIXS) endstation at the Advanced Light Source

NASA Astrophysics Data System (ADS)

Qiao, Ruimin; Li, Qinghao; Zhuo, Zengqing; Sallis, Shawn; Fuchs, Oliver; Blum, Monika; Weinhardt, Lothar; Heske, Clemens; Pepper, John; Jones, Michael; Brown, Adam; Spucces, Adrian; Chow, Ken; Smith, Brian; Glans, Per-Anders; Chen, Yanxue; Yan, Shishen; Pan, Feng; Piper, Louis F. J.; Denlinger, Jonathan; Guo, Jinghua; Hussain, Zahid; Chuang, Yi-De; Yang, Wanli

2017-03-01

An endstation with two high-efficiency soft x-ray spectrographs was developed at Beamline 8.0.1 of the Advanced Light Source, Lawrence Berkeley National Laboratory. The endstation is capable of performing soft x-ray absorption spectroscopy, emission spectroscopy, and, in particular, resonant inelastic soft x-ray scattering (RIXS). Two slit-less variable line-spacing grating spectrographs are installed at different detection geometries. The endstation covers the photon energy range from 80 to 1500 eV. For studying transition-metal oxides, the large detection energy window allows a simultaneous collection of x-ray emission spectra with energies ranging from the O K-edge to the Ni L-edge without moving any mechanical components. The record-high efficiency enables the recording of comprehensive two-dimensional RIXS maps with good statistics within a short acquisition time. By virtue of the large energy window and high throughput of the spectrographs, partial fluorescence yield and inverse partial fluorescence yield signals could be obtained for all transition metal L-edges including Mn. Moreover, the different geometries of these two spectrographs (parallel and perpendicular to the horizontal polarization of the beamline) provide contrasts in RIXS features with two different momentum transfers.

Reflection soft X-ray microscope and method

DOEpatents

Suckewer, Szymon; Skinner, Charles H.; Rosser, Roy

1993-01-01

A reflection soft X-ray microscope is provided by generating soft X-ray beams, condensing the X-ray beams to strike a surface of an object at a predetermined angle, and focusing the X-ray beams reflected from the surface onto a detector, for recording an image of the surface or near surface features of the object under observation.

Reflection soft X-ray microscope and method

DOEpatents

Suckewer, S.; Skinner, C.H.; Rosser, R.

1993-01-05

A reflection soft X-ray microscope is provided by generating soft X-ray beams, condensing the X-ray beams to strike a surface of an object at a predetermined angle, and focusing the X-ray beams reflected from the surface onto a detector, for recording an image of the surface or near surface features of the object under observation.

Search for Hard X-Ray Emission from the Soft X-Ray Transient Aquila X-1

NASA Astrophysics Data System (ADS)

Harmon, B. A.; Zhang, S. N.; Paciesas, W. S.; Tavani, M.; Kaaret, P.; Ford, E.

1994-12-01

We are investigating the possibility of hard x-ray emission from the recurrent soft x-ray transient and x-ray burst source Aquila X-1 (Aql X-1). Outbursts of this source are relatively frequent with a spacing of ~ 4-10 months (Kitamoto, S. et al. 1993, ApJ, 403, 315). The recent detections of hard tails (\\(>\\)20 keV) in low luminosity x-ray bursters (Barret, D. & Vedrenne, G. 1994, ApJ Supp. S. 92, 505) suggest that neutron star transient systems such as Aql X-1 can produce hard x-ray emission which is detectable by BATSE. We are correlating reported optical and soft x-ray observations since 1991 of Aql X-1 with BATSE observations in order to search for hard x-ray emission episodes, and to study their temporal and spectral evolution. We will present preliminary results of this search in the 20-1000 keV band using the Earth occultation technique applied to the large area detectors. If this work is successful, we hope to alert the astronomical community for the next Aql X-1 outburst expected in 1995. Simultaneous x-ray/hard x-ray and optical observations of Aql X-1 during outburst would be of great importance for the modeling of soft x-ray transients and related systems.

High-efficiency in situ resonant inelastic x-ray scattering (iRIXS) endstation at the Advanced Light Source

DOE PAGES

Qiao, Ruimin; Li, Qinghao; Zhuo, Zengqing; ...

2017-03-17

In this paper, an endstation with two high-efficiency soft x-ray spectrographs was developed at Beamline 8.0.1 of the Advanced Light Source, Lawrence Berkeley National Laboratory. The endstation is capable of performing soft x-ray absorption spectroscopy, emission spectroscopy, and, in particular, resonant inelastic soft x-ray scattering (RIXS). Two slit-less variable line-spacing grating spectrographs are installed at different detection geometries. The endstation covers the photon energy range from 80 to 1500 eV. For studying transition-metal oxides, the large detection energy window allows a simultaneous collection of x-ray emission spectra with energies ranging from the O K-edge to the Ni L-edge without movingmore » any mechanical components. The record-high efficiency enables the recording of comprehensive two-dimensional RIXS maps with good statistics within a short acquisition time. By virtue of the large energy window and high throughput of the spectrographs, partial fluorescence yield and inverse partial fluorescence yield signals could be obtained for all transition metal L-edges including Mn. Finally and moreover, the different geometries of these two spectrographs (parallel and perpendicular to the horizontal polarization of the beamline) provide contrasts in RIXS features with two different momentum transfers.« less

X-Ray Emission from the Soft X-Ray Transient Aquila X-1

NASA Technical Reports Server (NTRS)

Tavani, Marco

1998-01-01

Aquila X-1 is the most prolific of soft X-ray transients. It is believed to contain a rapidly spinning neutron star sporadically accreting near the Eddington limit from a low-mass companion star. The interest in studying the repeated X-ray outbursts from Aquila X-1 is twofold: (1) studying the relation between optical, soft and hard X-ray emission during the outburst onset, development and decay; (2) relating the spectral component to thermal and non-thermal processes occurring near the magnetosphere and in the boundary layer of a time-variable accretion disk. Our investigation is based on the BATSE monitoring of Aquila X-1 performed by our group. We observed Aquila X-1 in 1997 and re-analyzed archival information obtained in April 1994 during a period of extraordinary outbursting activity of the source in the hard X-ray range. Our results allow, for the first time for this important source, to obtain simultaneous spectral information from 2 keV to 200 keV. A black body (T = 0.8 keV) plus a broken power-law spectrum describe accurately the 1994 spectrum. Substantial hard X-ray emission is evident in the data, confirming that the accretion phase during sub-Eddington limit episodes is capable of producing energetic hard emission near 5 x 10(exp 35) ergs(exp -1). A preliminary paper summarizes our results, and a more comprehensive account is being written. We performed a theoretical analysis of possible emission mechanisms, and confirmed that a non-thermal emission mechanism triggered in a highly sheared magnetosphere at the accretion disk inner boundary can explain the hard X-ray emission. An anticorrelation between soft and hard X-ray emission is indeed prominently observed as predicted by this model.

Burning plasmas with ultrashort soft-x-ray flashing

NASA Astrophysics Data System (ADS)

Hu, S. X.; Goncharov, V. N.; Skupsky, S.

2012-07-01

Fast ignition with narrow-band coherent x-ray pulses has been revisited for cryogenic deuterium-tritium (DT) plasma conditions achieved on the OMEGA Laser System. In contrast to using hard-x-rays (hv = 3-6 keV) proposed in the original x-ray fast-ignition proposal, we find that soft-x-ray sources with hv ≈ 500 eV photons can be suitable for igniting the dense DT-plasmas achieved on OMEGA. Two-dimensional radiation-hydrodynamics simulations have identified the break-even conditions for realizing such a "hybrid" ignition scheme (direct-drive compression with soft-x-ray heating) with 50-μm-offset targets: ˜10 ps soft-x-ray pulse (hv ≈ 500 eV) with a total energy of 500-1000 J to be focused into a 10 μm spot-size. A variety of x-ray pulse parameters have also been investigated for optimization. It is noted that an order of magnitude increase in neutron yield has been predicted even with x-ray energy as low as ˜50 J. Scaling this idea to a 1 MJ large-scale target, a gain above ˜30 can be reached with the same soft-x-ray pulse at 1.65 kJ energy. Even though such energetic x-ray sources do not currently exist, we hope that the proposed ignition scheme may stimulate efforts on generating powerful soft-x-ray sources in the near future.

High-resolution soft X-ray beamline ADRESS at the Swiss Light Source for resonant inelastic X-ray scattering and angle-resolved photoelectron spectroscopies

PubMed Central

Strocov, V. N.; Schmitt, T.; Flechsig, U.; Schmidt, T.; Imhof, A.; Chen, Q.; Raabe, J.; Betemps, R.; Zimoch, D.; Krempasky, J.; Wang, X.; Grioni, M.; Piazzalunga, A.; Patthey, L.

2010-01-01

The concepts and technical realisation of the high-resolution soft X-ray beamline ADRESS operating in the energy range from 300 to 1600 eV and intended for resonant inelastic X-ray scattering (RIXS) and angle-resolved photoelectron spectroscopy (ARPES) are described. The photon source is an undulator of novel fixed-gap design where longitudinal movement of permanent magnetic arrays controls not only the light polarization (including circular and 0–180° rotatable linear polarizations) but also the energy without changing the gap. The beamline optics is based on the well established scheme of plane-grating monochromator operating in collimated light. The ultimate resolving power E/ΔE is above 33000 at 1 keV photon energy. The choice of blazed versus lamellar gratings and optimization of their profile parameters is described. Owing to glancing angles on the mirrors as well as optimized groove densities and profiles of the gratings, the beamline is capable of delivering high photon flux up to 1 × 1013 photons s−1 (0.01% BW)−1 at 1 keV. Ellipsoidal refocusing optics used for the RIXS endstation demagnifies the vertical spot size down to 4 µm, which allows slitless operation and thus maximal transmission of the high-resolution RIXS spectrometer delivering E/ΔE > 11000 at 1 keV photon energy. Apart from the beamline optics, an overview of the control system is given, the diagnostics and software tools are described, and strategies used for the optical alignment are discussed. An introduction to the concepts and instrumental realisation of the ARPES and RIXS endstations is given. PMID:20724785

Resonant Soft X-ray Scattering studies with Transition Edge Sensors

NASA Astrophysics Data System (ADS)

Fang, Yizhi; Lee, Sangjun; de La Pena, Gilberto; Sun, Xiaolan; Rodolakis, Fanny; McChesney, Jessica; Fowler, Joe; Joe, Young Il; Doriese, William; Morgan, Kelsey; Swetz, Daniel; Ullom, Joel; Abbamonte, Peter

Resonant Soft X-ray has been one of the key techniques to study charge orders in high Tc cuperates. To solve the issue of unwanted enhancement of inelastic florescence background at resonance, we have developed an energy-resolving superconducting Transition-Edge Sensor microcalorimeters. These superconducting sensors obtain exquisite energy resolution by exploiting the superconducting-to-normal transition to photon energy and by operating at cryogenic temperatures ( 70 mK) where thermal noise is minimal. This TES has demonstrated 1.0 eV resolution below 1 keV. We present first results using this detector to study the (002) Bragg peak and specular elastic scattering from a single crystal of stripe-ordered La 2 - x Bax CuO4 (x=0.125). Use of this detector for studying excitations and rejecting background fluorescence will be discussed.

Revealing the electronic structure of LiC 6 by soft X-ray spectroscopy

DOE PAGES

Zhang, L.; Li, X.; Augustsson, A.; ...

2017-03-09

The electronic structure of LiC 6 has been investigated in this paper by soft X-ray absorption and emission spectroscopies. The results reveal that upon full lithiation of graphite, the Li 2s electrons are transferred into the carbon π* states in a near rigid-band behavior, resulting in the increased density of states near E F and the shift of σ* states to lower energies. Finally, in addition, the resonant inelastic X-ray scattering spectra of LiC 6 do not show strong dispersive features as that of graphite, indicating that the crystal momentum is not conserved during the scattering process due to themore » delocalization of electrons in the intermediate state.« less

Fingerprints of electronic, spin and structural dynamics from resonant inelastic soft X-ray scattering in transient photo-chemical species

DOE PAGES

Norell, Jesper; Jay, Raphael M.; Hantschmann, Markus; ...

2018-02-20

Here, we describe how inversion symmetry separation of electronic state manifolds in resonant inelastic soft X-ray scattering (RIXS) can be applied to probe excited-state dynamics with compelling selectivity. In a case study of Fe L 3-edge RIXS in the ferricyanide complex Fe(CN) 6 3-, we demonstrate with multi-configurational restricted active space spectrum simulations how the information content of RIXS spectral fingerprints can be used to unambiguously separate species of different electronic configurations, spin multiplicities, and structures, with possible involvement in the decay dynamics of photo-excited ligand-to-metal charge-transfer. Specifically, we propose that this could be applied to confirm or reject themore » presence of a hitherto elusive transient Quartet species. Thus, RIXS offers a particular possibility to settle a recent controversy regarding the decay pathway, and we expect the technique to be similarly applicable in other model systems of photo-induced dynamics.« less

Fingerprints of electronic, spin and structural dynamics from resonant inelastic soft X-ray scattering in transient photo-chemical species

DOE Office of Scientific and Technical Information (OSTI.GOV)

Norell, Jesper; Jay, Raphael M.; Hantschmann, Markus

Here, we describe how inversion symmetry separation of electronic state manifolds in resonant inelastic soft X-ray scattering (RIXS) can be applied to probe excited-state dynamics with compelling selectivity. In a case study of Fe L 3-edge RIXS in the ferricyanide complex Fe(CN) 6 3-, we demonstrate with multi-configurational restricted active space spectrum simulations how the information content of RIXS spectral fingerprints can be used to unambiguously separate species of different electronic configurations, spin multiplicities, and structures, with possible involvement in the decay dynamics of photo-excited ligand-to-metal charge-transfer. Specifically, we propose that this could be applied to confirm or reject themore » presence of a hitherto elusive transient Quartet species. Thus, RIXS offers a particular possibility to settle a recent controversy regarding the decay pathway, and we expect the technique to be similarly applicable in other model systems of photo-induced dynamics.« less

Electronic structure and magnetic properties of the half-metallic ferrimagnet Mn2VAl probed by soft x-ray spectroscopies

NASA Astrophysics Data System (ADS)

Nagai, K.; Fujiwara, H.; Aratani, H.; Fujioka, S.; Yomosa, H.; Nakatani, Y.; Kiss, T.; Sekiyama, A.; Kuroda, F.; Fujii, H.; Oguchi, T.; Tanaka, A.; Miyawaki, J.; Harada, Y.; Takeda, Y.; Saitoh, Y.; Suga, S.; Umetsu, R. Y.

2018-01-01

We have studied the electronic structure of ferrimagnetic Mn2VAl single crystals by means of soft x-ray absorption spectroscopy (XAS), x-ray absorption magnetic circular dichroism (XMCD), and resonant soft x-ray inelastic scattering (RIXS). We have successfully observed the XMCD signals for all the constituent elements. The Mn L2 ,3 XAS and XMCD spectra are reproduced by spectral simulations based on density-functional theory, indicating the itinerant character of the Mn 3 d states. On the other hand, the V 3 d electrons are rather localized since the ionic model can qualitatively explain the V L2 ,3 XAS and XMCD spectra. This picture is consistent with local d d excitations revealed by the V L3 RIXS.

Focusing polycapillary to reduce parasitic scattering for inelastic x-ray measurements at high pressure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chow, P., E-mail: pchow@carnegiescience.edu; Xiao, Y. M.; Rod, E.

2015-07-15

The double-differential scattering cross-section for the inelastic scattering of x-ray photons from electrons is typically orders of magnitude smaller than that of elastic scattering. With samples 10-100 μm size in a diamond anvil cell at high pressure, the inelastic x-ray scattering signals from samples are obscured by scattering from the cell gasket and diamonds. One major experimental challenge is to measure a clean inelastic signal from the sample in a diamond anvil cell. Among the many strategies for doing this, we have used a focusing polycapillary as a post-sample optic, which allows essentially only scattered photons within its input fieldmore » of view to be refocused and transmitted to the backscattering energy analyzer of the spectrometer. We describe the modified inelastic x-ray spectrometer and its alignment. With a focused incident beam which matches the sample size and the field of view of polycapillary, at relatively large scattering angles, the polycapillary effectively reduces parasitic scattering from the diamond anvil cell gasket and diamonds. Raw data collected from the helium exciton measured by x-ray inelastic scattering at high pressure using the polycapillary method are compared with those using conventional post-sample slit collimation.« less

Soft X-Ray Emissions from Planets and Moons

NASA Technical Reports Server (NTRS)

Bhardwaj, A.; Gladstone, G. R.; Elsner, R. F.; Waite, J. H., Jr.; Grodent, D.; Lewis, W. S.; Crary, F. J.; Weisskopf, M. C.; Howell, R. R.; Johnson, R. E.;

The very soft X-ray emission of X-ray-faint early-type galaxies

NASA Technical Reports Server (NTRS)

Pellegrini, S.; Fabbiano, G.

1994-01-01

A recent reanaylsis of Einstein data, and new ROSAT observations, have revealed the presence of at least two components in the X-ray spectra of X-ray faint early-type galaxies: a relatively hard component (kT greater than 1.5 keV), and a very soft component (kT approximately 0.2-0.3 keV). In this paper we address the problem of the nature of the very soft component and whether it can be due to a hot interstellar medium (ISM), or is most likely originated by the collective emission of very soft stellar sources. To this purpose, hydrodynamical evolutionary sequences for the secular behavior of gas flows in ellipticals have been performed, varying the Type Ia supernovae rate of explosion, and the dark matter amount and distribution. The results are compared with the observational X-ray data: the average Einstein spectrum for six X-ray faint early-type galaxies (among which are NGC 4365 and NGC 4697), and the spectrum obtained by the ROSAT pointed observation of NGC 4365. The very soft component could be entirely explained with a hot ISM only in galaxies such as NGC 4697, i.e., when the depth of the potential well-on which the average ISM temperature strongly depends-is quite shallow; in NGC 4365 a diffuse hot ISM would have a temperature larger than that of the very soft component, because of the deeper potential well. So, in NGC 4365 the softest contribution to the X-ray emission comes certainly from stellar sources. As stellar soft X-ray emitters, we consider late-type stellar coronae, supersoft sources such as those discovered by ROSAT in the Magellanic Clouds and M31, and RS CVn systems. All these candidates can be substantial contributors to the very soft emission, though none of them, taken separately, plausibly accounts entirely for its properties. We finally present a model for the X-ray emission of NGC 4365, to reproduce in detail the results of the ROSAT pointed observation, including the Position Sensitive Proportional Counter (PSPC) spectrum and radial

High-order multilayer coated blazed gratings for high resolution soft x-ray spectroscopy

DOE PAGES

Voronov, Dmitriy L.; Goray, Leonid I.; Warwick, Tony; ...

2015-02-17

A grand challenge in soft x-ray spectroscopy is to drive the resolving power of monochromators and spectrometers from the 10 4 achieved routinely today to well above 10 5. This need is driven mainly by the requirements of a new technique that is set to have enormous impact in condensed matter physics, Resonant Inelastic X-ray Scattering (RIXS). Unlike x-ray absorption spectroscopy, RIXS is not limited by an energy resolution dictated by the core-hole lifetime in the excitation process. Using much higher resolving power than used for normal x-ray absorption spectroscopy enables access to the energy scale of soft excitations inmore » matter. These excitations such as magnons and phonons drive the collective phenomena seen in correlated electronic materials such as high temperature superconductors. RIXS opens a new path to study these excitations at a level of detail not formerly possible. However, as the process involves resonant excitation at an energy of around 1 keV, and the energy scale of the excitations one would like to see are at the meV level, to fully utilize the technique requires the development of monochromators and spectrometers with one to two orders of magnitude higher energy resolution than has been conventionally possible. Here we investigate the detailed diffraction characteristics of multilayer blazed gratings. These elements offer potentially revolutionary performance as the dispersive element in ultra-high resolution x-ray spectroscopy. In doing so, we have established a roadmap for the complete optimization of the grating design. Traditionally 1st order gratings are used in the soft x-ray region, but we show that as in the optical domain, one can work in very high spectral orders and thus dramatically improve resolution without significant loss in efficiency.« less

Dante Soft X-ray Power Diagnostic for NIF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dewald, E; Campbell, K; Turner, R

2004-04-15

Soft x-ray power diagnostics are essential for measuring spectrally resolved the total x-ray flux, radiation temperature, conversion efficiency and albedo that are important quantities for the energetics of indirect drive hohlraums. At the Nova or Omega Laser Facilities, these measurements are performed mainly with Dante, but also with DMX and photo-conductive detectors (PCD's). The Dante broadband spectrometer is a collection of absolute calibrated vacuum x-ray diodes, thin filters and x-ray mirrors used to measure the soft x-ray emission for photon energies above 50 eV.

Soft x-ray spectroscopy studies of novel electronic materials using synchrotron radiation

NASA Astrophysics Data System (ADS)

Newby, David, Jr.

surface evolution of these films is discussed, and the effects of different gas environments on oxygen vacancy concentration are elucidated. LSMO is commonly used in commercial fuel cell devices. Here the resonant soft x-ray emission (RIXS) spectrum of LSMO is examined, and it is shown that the inelastic x-ray emission structure of LSMO arises from local atomic multiplet effects.

Soft X-ray absorption spectroscopy and resonant inelastic X-ray scattering spectroscopy below 100 eV: probing first-row transition-metal M-edges in chemical complexes.

PubMed

Wang, Hongxin; Young, Anthony T; Guo, Jinghua; Cramer, Stephen P; Friedrich, Stephan; Braun, Artur; Gu, Weiwei

2013-07-01

X-ray absorption and scattering spectroscopies involving the 3d transition-metal K- and L-edges have a long history in studying inorganic and bioinorganic molecules. However, there have been very few studies using the M-edges, which are below 100 eV. Synchrotron-based X-ray sources can have higher energy resolution at M-edges. M-edge X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray scattering (RIXS) could therefore provide complementary information to K- and L-edge spectroscopies. In this study, M2,3-edge XAS on several Co, Ni and Cu complexes are measured and their spectral information, such as chemical shifts and covalency effects, are analyzed and discussed. In addition, M2,3-edge RIXS on NiO, NiF2 and two other covalent complexes have been performed and different d-d transition patterns have been observed. Although still preliminary, this work on 3d metal complexes demonstrates the potential to use M-edge XAS and RIXS on more complicated 3d metal complexes in the future. The potential for using high-sensitivity and high-resolution superconducting tunnel junction X-ray detectors below 100 eV is also illustrated and discussed.

Filters for soft X-ray solar telescopes

NASA Technical Reports Server (NTRS)

Spiller, Eberhard; Grebe, Kurt; Golub, Leon

1990-01-01

Soft X-ray telescopes require filters that block visible and infrared light and have good soft X-ray transmission. The optical properties of possible materials are discussed, and the fabrication and testing methods for the filters used in a 10-inch normal incidence telescope for 63 A are described. The best performances in the 44-114-A wavelength range are obtained with foils of carbon and rhodium.

Intensity correlation measurement system by picosecond single shot soft x-ray laser.

PubMed

Kishimoto, Maki; Namikawa, Kazumichi; Sukegawa, Kouta; Yamatani, Hiroshi; Hasegawa, Noboru; Tanaka, Momoko

2010-01-01

We developed a new soft x-ray speckle intensity correlation spectroscopy system by use of a single shot high brilliant plasma soft x-ray laser. The plasma soft x-ray laser is characterized by several picoseconds in pulse width, more than 90% special coherence, and 10(11) soft x-ray photons within a single pulse. We developed a Michelson type delay pulse generator using a soft x-ray beam splitter to measure the intensity correlation of x-ray speckles from materials and succeeded in generating double coherent x-ray pulses with picosecond delay times. Moreover, we employed a high-speed soft x-ray streak camera for the picosecond time-resolved measurement of x-ray speckles caused by double coherent x-ray pulse illumination. We performed the x-ray speckle intensity correlation measurements for probing the relaxation phenomena of polarizations in polarization clusters in the paraelectric phase of the ferroelectric material BaTiO(3) near its Curie temperature and verified its performance.

The Soft X-ray View of Ultra Fast Outflows

NASA Astrophysics Data System (ADS)

Reeves, J.; Braito, V.; Nardini, E.; Matzeu, G.; Lobban, A.; Costa, M.; Pounds, K.; Tombesi, F.; Behar, E.

2017-10-01

The recent large XMM-Newton programmes on the nearby quasars PDS 456 and PG 1211+143 have revealed prototype ultra fast outflows in the iron K band through highly blue shifted absorption lines. The wind velocities are in excess of 0.1c and are likely to make a significant contribution to the host galaxy feedback. Here we present evidence for the signature of the fast wind in the soft X-ray band from these luminous quasars, focusing on the spectroscopy with the RGS. In PDS 456, the RGS spectra reveal the presence of soft X-ray broad absorption line profiles, which suggests that PDS 456 is an X-ray equivalent to the BAL quasars, with outflow velocities reaching 0.2c. In PG 1211, the soft X-ray RGS spectra show a complex of several highly blue shifted absorption lines over a wide range of ionisation and reveal outflowing components with velocities between 0.06-0.17c. For both quasars, the soft X-ray absorption is highly variable, even on timescales of days and is most prominent when the quasar flux is low. Overall the results imply the presence of a soft X-ray component of the ultra fast outflows, which we attribute to a clumpy or inhomogeneous phase of the disk wind.

Understanding the X-ray spectrum of anomalous X-ray pulsars and soft gamma-ray repeaters

NASA Astrophysics Data System (ADS)

Guo, Yan-Jun; Dai, Shi; Li, Zhao-Sheng; Liu, Yuan; Tong, Hao; Xu, Ren-Xin

2015-04-01

Hard X-rays above 10 keV are detected from several anomalous X-ray pulsars (AXPs) and soft gamma-ray repeaters (SGRs), and different models have been proposed to explain the physical origin within the frame of either a magnetar model or a fallback disk system. Using data from Suzaku and INTEGRAL, we study the soft and hard X-ray spectra of four AXPs/SGRs: 1RXS J170849-400910, 1E 1547.0-5408, SGR 1806-20 and SGR 0501+4516. It is found that the spectra could be well reproduced by the bulk-motion Comptonization (BMC) process as was first suggested by Trümper et al., showing that the accretion scenario could be compatible with X-ray emission from AXPs/SGRs. Simulated results from the Hard X-ray Modulation Telescope using the BMC model show that the spectra would have discrepancies from the power-law, especially the cutoff at ˜200 keV. Thus future observations will allow researchers to distinguish different models of the hard X-ray emission and will help us understand the nature of AXPs/SGRs. Supported by the National Natural Science Foundation of China.

Soft X-Ray Emissions from Planets and Moons

NASA Technical Reports Server (NTRS)

Bhardwaj, A.; Gladstone, G. R.; Elsner, R. F.; Waite, J. H., Jr.; Grodent, D.; Cravens, T. E.; Howell, R. R.; Metzger, A. E.; Ostgaard, N.; Maurellis, A.;

Towards 10 meV resolution: The design of an ultrahigh resolution soft X-ray RIXS spectrometer

DOE PAGES

Dvorak, Joseph; Jarrige, Ignace; Bisogni, Valentina; ...

2016-11-10

Here we present the optical design of the Centurion soft X-ray resonant inelastic X-ray scattering (RIXS) spectrometer to be located on the SIX beamline at NSLS-II. The spectrometer is designed to reach a resolving power of 100 000 at 1000 eV at its best resolution. It is also designed to have continuously variable 2θ motion over a range of 112° using a custom triple rotating flange. We have analyzed several possible spectrometer designs capable of reaching the target resolution. After careful analysis, we have adopted a Hettrick-Underwood spectrometer design, with an additional plane mirror to maintain a fixed direction formore » the outgoing beam. The spectrometer can cancel defocus and coma aberrations at all energies, has an erect focal plane, and minimizes mechanical motions of the detector. When the beamline resolution is accounted for, the net spectral resolution will be 14 meV at 1000 eV. Lastly, this will open up many low energy excitations to study and will expand greatly the power of soft X-ray RIXS.« less

Towards 10 meV resolution: The design of an ultrahigh resolution soft X-ray RIXS spectrometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dvorak, Joseph; Jarrige, Ignace; Bisogni, Valentina

Here we present the optical design of the Centurion soft X-ray resonant inelastic X-ray scattering (RIXS) spectrometer to be located on the SIX beamline at NSLS-II. The spectrometer is designed to reach a resolving power of 100 000 at 1000 eV at its best resolution. It is also designed to have continuously variable 2θ motion over a range of 112° using a custom triple rotating flange. We have analyzed several possible spectrometer designs capable of reaching the target resolution. After careful analysis, we have adopted a Hettrick-Underwood spectrometer design, with an additional plane mirror to maintain a fixed direction formore » the outgoing beam. The spectrometer can cancel defocus and coma aberrations at all energies, has an erect focal plane, and minimizes mechanical motions of the detector. When the beamline resolution is accounted for, the net spectral resolution will be 14 meV at 1000 eV. Lastly, this will open up many low energy excitations to study and will expand greatly the power of soft X-ray RIXS.« less

Plane-grating flat-field soft x-ray spectrometer

NASA Astrophysics Data System (ADS)

Hague, C. F.; Underwood, J. H.; Avila, A.; Delaunay, R.; Ringuenet, H.; Marsi, M.; Sacchi, M.

2005-02-01

We describe a soft x-ray spectrometer covering the 120-800 eV range. It is intended for resonant inelastic x-ray scattering experiments performed at third generation synchrotron radiation (SR) facilities and has been developed with SOLEIL, the future French national SR source in mind. The Hettrick-Underwood principle is at the heart of the design using a combination of varied line-spacing plane grating and spherical-mirror to provide a flat-field image. It is slitless for optimum acceptance. This means the source size determines the resolving power. A spot size of ⩽5μm is planned at SOLEIL which, according to simulations, should ensure a resolving power ⩾1000 over the whole energy range. A 1024×1024 pixel charge-coupled device (CCD) with a 13μm×13μm pixel size is used. This is an improvement on the use of microchannel-plate detectors, both as concerns efficiency and spatial resolution. Additionally spectral line curvature is avoided by the use of a horizontal focusing mirror concentrating the beam in the nondispersing direction. It allows for readout using a binning mode to reduce the intrinsically large CCD readout noise. Preliminary results taken at beamlines at Elettra (Trieste) and at BESSY (Berlin) are presented.

TOPICAL REVIEW: Human soft tissue analysis using x-ray or gamma-ray techniques

NASA Astrophysics Data System (ADS)

Theodorakou, C.; Farquharson, M. J.

2008-06-01

This topical review is intended to describe the x-ray techniques used for human soft tissue analysis. X-ray techniques have been applied to human soft tissue characterization and interesting results have been presented over the last few decades. The motivation behind such studies is to provide improved patient outcome by using the data obtained to better understand a disease process and improve diagnosis. An overview of theoretical background as well as a complete set of references is presented. For each study, a brief summary of the methodology and results is given. The x-ray techniques include x-ray diffraction, x-ray fluorescence, Compton scattering, Compton to coherent scattering ratio and attenuation measurements. The soft tissues that have been classified using x-rays or gamma rays include brain, breast, colon, fat, kidney, liver, lung, muscle, prostate, skin, thyroid and uterus.

Toroidal silicon polarization analyzer for resonant inelastic x-ray scattering

DOE PAGES

Gao, Xuan; Casa, Diego; Kim, Jungho; ...

2016-08-15

Resonant Inelastic X-ray Scattering (RIXS) is a powerful probe for studying electronic excitations in materials. Standard high energy RIXS measurements do not measure the polarization of the scattered x-rays, which is unfortunate since it carries information about the nature and symmetry of the excitations involved in the scattering process. Moreover we report the fabrication of thin Si-based polarization analyzers with a double-concave toroidal surface, useful for L-edge RIXS studies in heavier atoms such as the 5-d transition metals.

Inelastic X-ray Scattering from Shocked Liquid Deuterium

DOE PAGES

Regan, S. P.; Falk, K.; Gregori, G.; ...

2012-12-28

The Fermi-degenerate plasma conditions created in liquid deuterium by a laser-ablation—driven shock wave were probed with noncollective, spectrally resolved, inelastic x-ray Thomson scattering employing Cl Ly α line emission at 2.96 keV. Thus, these first x-ray Thomson scattering measurements of the microscopic properties of shocked deuterium show an inferred spatially averaged electron temperature of 8±5 eV, an electron density of 2.2(±0.5)×10 23 cm -3, and an ionization of 0.8 (-0.25, +0.15). Our two-dimensional hydrodynamic simulations using equation-of-state models suited for the extreme parameters occurring in inertial confinement fusion research and planetary interiors are consistent with the experimental results.

Soft x ray properties of the Geminga pulsar

NASA Technical Reports Server (NTRS)

Halpern, J. P.; Ruderman, M.

1993-01-01

The ROSAT soft x ray spectrum and pulse profile of the Geminga pulsar are analyzed and interpreted in terms of thermal emission from the surface of the neutron star. The x ray spectrum appears to consist of two blackbody components with T(sub 1) = (5.2 +/- 1.0) x 10 (exp 5) K and T(sub 2) approximately 3 x 10(exp 6) K, respectively. The inferred ratio of surface areas, A(sub 2)/A(sub 1), is approximately 3 x 10(exp -5). Both components are highly modulated at the pulsar rotation period, but the harder x ray pulse is narrower, and leads the main (soft) x ray pulse by about 105 deg of phase. The soft x ray component is interpreted as photospheric cooling of much of the neutron star's surface area, while the small, hot region could be part of the much smaller polar cap heated by energetic particles flowing inward from the magnetospheric accelerator which is responsible for the production of Geminga's gamma rays. Geminga's gamma ray emission is consistent with outer-magnetosphere accelerator models for highly inclined dipoles. These predict the beaming of energetic gamma rays close enough to the star to give copious e(+/-) production in the stellar magnetic field and a large circumstellar pair density from pair inflow toward the surface. These pairs may quench radio emission, and also reflect most of the hard polar cap x rays back to the stellar surface by cyclotron resonance scattering. They are then reemitted from that much larger area at the lower temperature T(sub 1). The single-peaked nature of the x ray pulse and its energy-dependent phase suggest an off-center dipole geometry for the surface magnetic field. Under the assumption that the soft x ray emission comes from the full surface of a neutron star of radius R = 10 km, a distance estimate of (150-400) pc is derived. This range is consistent with the fit interstellar column density of (1.5 +/- 0.5) x 10(exp 20) cm(exp -2). Distances less than 150 pc are probably ruled out both by the lower limit on the column

Soft X-ray results from the Wisconsin experiment on OSO-8

NASA Technical Reports Server (NTRS)

Bunner, A. N.

1978-01-01

Design features and capabilities of a soft X-ray instrument aboard OSO 8 are discussed, and results are presented for observations of AM Her, Her X-1, and Eta Car. The observations of AM Her indicate that: (1) the spectrum is composite, with a very steep or very-low-temperature component plus a rather flat or very-high-temperature component; (2) the relative phase of soft X-ray minimum and optical V-band primary minimum has remained stable over the interval between 1975 'high-state' observations and 1976 'low-state' observations; and (3) the times of soft X-ray minima and hard X-ray maxima coincide, to within the accuracy of the observations. For Her X-1, soft X-ray turn-on is found to lag behind hard X-ray turn-on by no more than 3 hr. It is suggested that little or no absorption of the soft X-ray component occurs during the on state by cool gas within the Her X-1 system. A strong source with a spectrum peaked between 0.4 and 1.5 keV has been detected which is consistent with a point source at the position of Eta Car.

Soft X-ray absorption spectroscopy and resonant inelastic X-ray scattering spectroscopy below 100 eV: probing first-row transition-metal M-edges in chemical complexes

PubMed Central

Wang, Hongxin; Young, Anthony T.; Guo, Jinghua; Cramer, Stephen P.; Friedrich, Stephan; Braun, Artur; Gu, Weiwei

2013-01-01

X-ray absorption and scattering spectroscopies involving the 3d transition-metal K- and L-edges have a long history in studying inorganic and bioinorganic molecules. However, there have been very few studies using the M-edges, which are below 100 eV. Synchrotron-based X-ray sources can have higher energy resolution at M-edges. M-edge X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray scattering (RIXS) could therefore provide complementary information to K- and L-edge spectroscopies. In this study, M 2,3-edge XAS on several Co, Ni and Cu complexes are measured and their spectral information, such as chemical shifts and covalency effects, are analyzed and discussed. In addition, M 2,3-edge RIXS on NiO, NiF2 and two other covalent complexes have been performed and different d–d transition patterns have been observed. Although still preliminary, this work on 3d metal complexes demonstrates the potential to use M-edge XAS and RIXS on more complicated 3d metal complexes in the future. The potential for using high-sensitivity and high-resolution superconducting tunnel junction X-ray detectors below 100 eV is also illustrated and discussed. PMID:23765304

Soft x-ray imaging using Polaroid Land films

NASA Astrophysics Data System (ADS)

Wong, C. S.; Choi, P.; Deeney, C.

1988-02-01

It is demonstrated in this note that optical Polaroid Land films can be used as a convenient detector in the soft x-ray region. The performance of Polaroid 667 film has been found to be comparable to that of the Kodak direct exposure film (DEF) for soft x-ray pinhole imaging. By a suitable choice of multiple filters, qualitative information about a dense plasma has been obtained.

Gain dynamics in a soft X-ray laser ampli er perturbed by a strong injected X-ray eld

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Yong; Wang, Shoujun; Oliva, E

2014-01-01

Seeding soft X-ray plasma ampli ers with high harmonics has been demonstrated to generate high-brightness soft X-ray laser pulses with full spatial and temporal coherence. The interaction between the injected coherent eld and the swept-gain medium has been modelled. However, no exper- iment has been conducted to probe the gain dynamics when perturbed by a strong external seed eld. Here, we report the rst X-ray pump X-ray probe measurement of the nonlinear response of a plasma ampli er perturbed by a strong soft X-ray ultra-short pulse. We injected a sequence of two time-delayed high-harmonic pulses (l518.9 nm) into a collisionallymore » excited nickel-like molybdenum plasma to measure with femto-second resolution the gain depletion induced by the saturated ampli cation of the high-harmonic pump and its subsequent recovery. The measured fast gain recovery in 1.5 1.75 ps con rms the possibility to generate ultra-intense, fully phase-coherent soft X-ray lasers by chirped pulse ampli cation in plasma ampli ers.« less

The Origin of Soft X-rays in DQ Herculis

NASA Technical Reports Server (NTRS)

White, Nicholas E. (Technical Monitor); Mukai, K.; Still, M.; Ringwald, F. A.

2002-01-01

DQ Herculis (Nova Herculis 1934) is a deeply eclipsing cataclysmic variable containing a magnetic white dwarf primary. The accretion disk is thought to block our line of sight to the white dwarf at all orbital phases due to its extreme inclination angle. Nevertheless, soft X-rays were detected from DQ Her with ROSAT PSPC. To probe the origin of these soft X-rays, we have performed Chandra ACIS observations. We confirm that DQ Her is an X-ray source. The bulk of the X-rays are from a point-like source and exhibit a shallow partial eclipse. We interpret this as due to scattering of the unseen central X-ray source, probably in an accretion disk wind. At the same time, we detect weak extended X-ray features around DQ Her, which we interpret as an X-ray emitting knot in the nova shell.

Low-energy d-d excitations in MnO studied by resonant x-ray fluorescence spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Butorin, S.M.; Guo, J.; Magnuson, M.

1997-04-01

Resonant soft X-ray emission spectroscopy has been demonstrated to possess interesting abilities for studies of electronic structure in various systems, such as symmetry probing, alignment and polarization dependence, sensitivity to channel interference, etc. In the present abstract the authors focus on the feasibility of resonant soft X-ray emission to probe low energy excitations by means of resonant electronic X-ray Raman scattering. Resonant X-ray emission can be regarded as an inelastic scattering process where a system in the ground state is transferred to a low excited state via a virtual core excitation. The energy closeness to a core excitation of themore » exciting radiation enhances the (generally) low probability for inelastic scattering at these wavelengths. Therefore soft X-ray emission spectroscopy (in resonant electronic Raman mode) can be used to study low energy d-d excitations in transition metal systems. The involvement of the intermediate core state allows one to use the selection rules of X-ray emission, and the appearance of the elastically scattered line in the spectra provides the reference to the ground state.« less

Resonant soft X-ray scattering on protein solutions

NASA Astrophysics Data System (ADS)

Ye, Dan; Le, Thinh; Wang, Cheng; Zwart, Peter; Gomez, Esther; Gomez, Enrique

Protein structure is crucial for biological function, such that characterizing protein folding and packing is important for the design of therapeutics and enzymes. We propose resonant soft X-ray scattering (RSOXS) as an approach to study proteins and other biological assemblies in solution. Calculations of the scattering contrast suggest that soft X-ray scattering is more sensitive than hard X-ray scattering, because of contrast generated at the absorption edges of constituent elements such as carbon, nitrogen and oxygen. We have examined the structure of bovine serum albumin (BSA) in solution by RSOXS. We find that by varying incident X-ray energies, we are able to achieve higher scattering contrast near the absorption edge. From our RSOXS scattering result we are able to reconstruct the structure of BSA in 3D. These RSOXS results also agree with hard X-ray experiments, including crystallographic data. Our study demonstrates the potential of RSOXS for studying protein structure in solution.

The Columbia University proton-induced soft x-ray microbeam.

PubMed

Harken, Andrew D; Randers-Pehrson, Gerhard; Johnson, Gary W; Brenner, David J

2011-09-15

A soft x-ray microbeam using proton-induced x-ray emission (PIXE) of characteristic titanium (K(α) 4.5 keV) as the x-ray source has been developed at the Radiological Research Accelerator Facility (RARAF) at Columbia University. The proton beam is focused to a 120 μm × 50 μm spot on the titanium target using an electrostatic quadrupole quadruplet previously used for the charged particle microbeam studies at RARAF. The proton induced x-rays from this spot project a 50 μm round x-ray generation spot into the vertical direction. The x-rays are focused to a spot size of 5 μm in diameter using a Fresnel zone plate. The x-rays have an attenuation length of (1/e length of ~145 μm) allowing more consistent dose delivery across the depth of a single cell layer and penetration into tissue samples than previous ultra soft x-ray systems. The irradiation end station is based on our previous design to allow quick comparison to charged particle experiments and for mixed irradiation experiments.

Soft X-ray Foucault test: A path to diffraction-limited imaging

NASA Astrophysics Data System (ADS)

Ray-Chaudhuri, A. K.; Ng, W.; Liang, S.; Cerrina, F.

1994-08-01

We present the development of a soft X-ray Foucault test capable of characterizing the imaging properties of a soft X-ray optical system at its operational wavelength and its operational configuration. This optical test enables direct visual inspection of imaging aberrations and provides real-time feedback for the alignment of high resolution soft X-ray optical systems. A first application of this optical test was carried out on a Mo-Si multilayer-coated Schwarzschild objective as part of the MAXIMUM project. Results from the alignment procedure are presented as well as the possibility for testing in the hard X-ray regime.

Soft X-ray observation of the Rho Ophiuchus dark cloud region

NASA Technical Reports Server (NTRS)

Apparao, K. M. V.; Hayakawa, S.; Hearn, D. R.

1979-01-01

Soft X-rays (0.1-0.8 keV) from the region including the Rho Oph dark cloud were observed with the SAS-3 low-energy X-ray telescope. No X-ray absorption by the cloud was observed. This indicates that the diffuse component of soft X-rays in this region is mostly from the foreground of the Rho Oph cloud which is located at a distance of 160-200 pc.

Science Objectives for a Soft X-ray Mission

NASA Astrophysics Data System (ADS)

Sibeck, D. G.; Connor, H. K.; Collier, M. R.; Collado-Vega, Y. M.; Walsh, B.

2016-12-01

When high charge state solar wind ions exchange electrons with exospheric neutrals, soft X-rays are emitted. In conjunction with flight- proven wide field-of-view soft X-ray imagers employing lobster-eye optics, recent simulations demonstrate the feasibility of imaging magnetospheric density structures such as the bow shock, magnetopause, and cusps. This presentation examines the Heliospheric scientific objectives that such imagers can address. Principal amongst these is the nature of reconnection at the dayside magnetopause: steady or transient, widespread or localized, component or antiparallel as a function of solar wind conditions. However, amongst many other objectives, soft X-ray imagers can provide crucial information concerning the structure of the bow shock as a function of solar wind Mach number and IMF orientation, the presence or absence of a depletion layer, the occurrence of Kelvin-Helmholtz or pressure-pulse driven magnetopause boundary waves, and the effects of radial IMF orientations and the foreshock upon bow shock and magnetopause location.

Soft x-ray streak camera for laser fusion applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stradling, G.L.

This thesis reviews the development and significance of the soft x-ray streak camera (SXRSC) in the context of inertial confinement fusion energy development. A brief introduction of laser fusion and laser fusion diagnostics is presented. The need for a soft x-ray streak camera as a laser fusion diagnostic is shown. Basic x-ray streak camera characteristics, design, and operation are reviewed. The SXRSC design criteria, the requirement for a subkilovolt x-ray transmitting window, and the resulting camera design are explained. Theory and design of reflector-filter pair combinations for three subkilovolt channels centered at 220 eV, 460 eV, and 620 eV aremore » also presented. Calibration experiments are explained and data showing a dynamic range of 1000 and a sweep speed of 134 psec/mm are presented. Sensitivity modifications to the soft x-ray streak camera for a high-power target shot are described. A preliminary investigation, using a stepped cathode, of the thickness dependence of the gold photocathode response is discussed. Data from a typical Argus laser gold-disk target experiment are shown.« less

Small scale H I structure and the soft X-ray background

NASA Technical Reports Server (NTRS)

Jahoda, K.; Mccammon, D.; Lockman, F. J.

1986-01-01

The observed anticorrelation between diffuse soft X-ray flux and H I column density has been explained as absorption of soft X-rays produced in a hot galactic halo, assuming that the neutral interstellar material is sufficiently clumped to reduce the soft X-ray absorption cross section by a factor of two to three. A 21 cm emission line study of H I column density variations at intermediate and high galactic latitudes to 10' spatial resolution has been done. The results confirm conclusions from preliminary work at coarser resolution, and in combination with other data appear to rule out the hypothesis that clumping of neutral interstellar matter on any angular scale significantly reduces X-ray absorption cross sections in the 0.13 - 0.28 keV energy range. It is concluded therefore that the observed anticorrelation is not primarily a consequence of absorption of soft X-rays produced in a hot galactic halo.

Simulation and optimization of the SIRIUS IPE soft x-ray beamline

NASA Astrophysics Data System (ADS)

Meyer, Bernd C.; Rocha, Tulio C. R.; Luiz, Sergio A. L.; C. Pinto, Artur; Westfahl, Harry

2017-08-01

The soft X-ray beamline IPE is one of the first phase SIRIUS beamlines at the LNLS, Brazil. Divided into two branches, IPE is designed to perform ambient pressure X-ray photo-electron spectroscopy (AP-XPS) and high resolution resonant inelastic X-ray scattering (RIXS) for samples in operando/environmental conditions inside cells and liquid jets. The aim is to maximize the photon flux in the energy range 200-1400 eV generated by an elliptically polarizing undulator source (EPU) and focus it to a 1 μm vertical spot size at the RIXS station and 10 μm at the AP-XPS station. In order to achieve the required resolving power (40.000 at 930 eV) for RIXS both the dispersion properties of the plane grating monochromator (PGM) and the thermal deformation of the optical elements need special attention. The grating parameters were optimized with the REFLEC code to maximize the efficiency at the required resolution. Thermal deformation of the PGM plane mirror limits the possible range of cff parameters depending of the photon energy used. Hence, resolution of the PGM and thermal deformation effects define the boundary conditions of the optical concept and the simulations of the IPE beamline. We compare simulations performed by geometrical ray-tracing (SHADOW) and wave front propagation (SRW) and show that wave front diffraction effects (apertures, optical surface error profiles) has a small effect on the beam spot size and shape.

Soft x-ray spectroscopy of high pressure liquid.

PubMed

Qiao, Ruimin; Xia, Yujian; Feng, Xuefei; Macdougall, James; Pepper, John; Armitage, Kevin; Borsos, Jason; Knauss, Kevin G; Lee, Namhey; Allézy, Arnaud; Gilbert, Benjamin; MacDowell, Alastair A; Liu, Yi-Sheng; Glans, Per-Anders; Sun, Xuhui; Chao, Weilun; Guo, Jinghua

2018-01-01

We describe a new experimental technique that allows for soft x-ray spectroscopy studies (∼100-1000 eV) of high pressure liquid (∼100 bars). We achieve this through a liquid cell with a 100 nm-thick Si 3 N 4 membrane window, which is sandwiched by two identical O-rings for vacuum sealing. The thin Si 3 N 4 membrane allows soft x-rays to penetrate, while separating the high-pressure liquid under investigation from the vacuum required for soft x-ray transmission and detection. The burst pressure of the Si 3 N 4 membrane increases with decreasing size and more specifically is inversely proportional to the side length of the square window. It also increases proportionally with the membrane thickness. Pressures > 60 bars could be achieved for 100 nm-thick square Si 3 N 4 windows that are smaller than 65 μm. However, above a certain pressure, the failure of the Si wafer becomes the limiting factor. The failure pressure of the Si wafer is sensitive to the wafer thickness. Moreover, the deformation of the Si 3 N 4 membrane is quantified using vertical scanning interferometry. As an example of the performance of the high-pressure liquid cell optimized for total-fluorescence detected soft x-ray absorption spectroscopy (sXAS), the sXAS spectra at the Ca L edge (∼350 eV) of a CaCl 2 aqueous solution are collected under different pressures up to 41 bars.

Soft x-ray spectroscopy of high pressure liquid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qiao, Ruimin; Xia, Yujian; Feng, Xuefei

Here, we describe a new experimental technique that allows for soft x-ray spectroscopy studies (~100-1000 eV) of high pressure liquid (~100 bars). We achieve this through a liquid cell with a 100 nm-thick Si 3N 4 membrane window, which is sandwiched by two identical O-rings for vacuum sealing. The thin Si 3N 4 membrane allows soft x-rays to penetrate, while separating the high-pressure liquid under investigation from the vacuum required for soft x-ray transmission and detection. The burst pressure of the Si 3N 4 membrane increases with decreasing size and more specifically is inversely proportional to the side length ofmore » the square window. It also increases proportionally with the membrane thickness. Pressures > 60 bars could be achieved for 100 nm-thick square Si 3N 4 windows that are smaller than 65 μm. However, above a certain pressure, the failure of the Si wafer becomes the limiting factor. The failure pressure of the Si wafer is sensitive to the wafer thickness. Moreover, the deformation of the Si 3N 4 membrane is quantified using vertical scanning interferometry. As an example of the performance of the high-pressure liquid cell optimized for total-fluorescence detected soft x-ray absorption spectroscopy (sXAS), the sXAS spectra at the Ca L edge (~350 eV) of a CaCl 2 aqueous solution are collected under different pressures up to 41 bars.« less

Soft x-ray spectroscopy of high pressure liquid

DOE PAGES

Qiao, Ruimin; Xia, Yujian; Feng, Xuefei; ...

2018-01-01

Here, we describe a new experimental technique that allows for soft x-ray spectroscopy studies (~100-1000 eV) of high pressure liquid (~100 bars). We achieve this through a liquid cell with a 100 nm-thick Si 3N 4 membrane window, which is sandwiched by two identical O-rings for vacuum sealing. The thin Si 3N 4 membrane allows soft x-rays to penetrate, while separating the high-pressure liquid under investigation from the vacuum required for soft x-ray transmission and detection. The burst pressure of the Si 3N 4 membrane increases with decreasing size and more specifically is inversely proportional to the side length ofmore » the square window. It also increases proportionally with the membrane thickness. Pressures > 60 bars could be achieved for 100 nm-thick square Si 3N 4 windows that are smaller than 65 μm. However, above a certain pressure, the failure of the Si wafer becomes the limiting factor. The failure pressure of the Si wafer is sensitive to the wafer thickness. Moreover, the deformation of the Si 3N 4 membrane is quantified using vertical scanning interferometry. As an example of the performance of the high-pressure liquid cell optimized for total-fluorescence detected soft x-ray absorption spectroscopy (sXAS), the sXAS spectra at the Ca L edge (~350 eV) of a CaCl 2 aqueous solution are collected under different pressures up to 41 bars.« less

Limits on soft X-ray flux from distant emission regions

NASA Technical Reports Server (NTRS)

Burrows, D. N.; Mccammon, D.; Sanders, W. T.; Kraushaar, W. L.

1984-01-01

The all-sky soft X-ray data of McCammon et al. and the new N sub H survey (Stark et al. was used to place limits on the amount of the soft X-ray diffuse background that can originate beyond the neutral gas of the galactic disk. The X-ray data for two regions of the sky near the galactic poles are shown to be uncorrelated with 21 cm column densities. Most of the observed x-ray flux must therefore originate on the near side of the most distant neutral gas. The results from these regions are consistent with X-ray emission from a locally isotropic, unabsorbed source, but require large variations in the emission of the local region over large angular scales.

Soft x-ray speckle from rough surfaces

NASA Astrophysics Data System (ADS)

Porter, Matthew Stanton

Dynamic light scattering has been of great use in determining diffusion times for polymer solutions. At the same time, polymer thin films are becoming of increasing importance, especially in the semiconductor industry where they are used as photoresists and interlevel dielectrics. As the dimensions of these devices decrease we will reach a point where lasers will no longer be able to probe the length scales of interest. Current laser wavelengths limit the size of observable diffusion lengths to 180-700 nm. This dissertation will discuss attempts at pushing dynamic fight scattering experiments into the soft x-ray region so that we can examine fluctuations in polymer thin films on the molecular length scale. The dissertation explores the possibility of carrying out a dynamic light scattering experiment in the soft x-ray regime. A detailed account of how to meet the basic requirements for a coherent scattering experiment in the soft x-ray regime win be given. In addition, a complete description of the chamber design will be discussed. We used our custom designed scattering chamber to collect reproducible coherent soft x-ray scattering data from etched silicon wafers and from polystyrene coated silicon wafers. The data from the silicon wafers followed the statistics for a well-developed speckle pattern while the data from the polystyrene films exhibited Poisson statistics. We used the data from both the etched wafers and the polystyrene coated wafers to place a lower limit of ~20 Å on the RMS surface roughness of samples which will produce well defined speckle patterns for the current detector setup. Future experiments which use the criteria set forth in this dissertation have the opportunity to be even more successful than this dissertation project.

X-ray Variations at the Orbital Period from Cygnus X-1 IN the High/Soft State

NASA Astrophysics Data System (ADS)

Boroson, Bram; Vrtilek, Saeqa Dil

2010-02-01

Orbital variability has been found in the X-ray hardness of the black hole candidate Cygnus X-1 during the soft/high X-ray state using light curves provided by the Rossi X-ray Timing Explorer's All-Sky Monitor. We are able to set broad limits on how the mass-loss rate and X-ray luminosity vary between the hard and soft states. The folded light curve shows diminished flux in the soft X-ray band at phi = 0 (defined as the time of the superior conjunction of the X-ray source). Models of the orbital variability provide slightly superior fits when the absorbing gas is concentrated in neutral clumps and better explain the strong variability in hardness. In combination with the previously established hard/low state dips, our observations give a lower limit to the mass-loss rate in the soft state (\\dot{M}<2× 10^{-6} M_{⊙} yr-1) than the limit in the hard state (\\dot{M}<4× 10^{-6} M_{⊙} yr-1). Without a change in the wind structure between X-ray states, the greater mass-loss rate during the low/hard state would be inconsistent with the increased flaring seen during the high-soft state.

Debris-free soft x-ray source with gas-puff target

NASA Astrophysics Data System (ADS)

Ni, Qiliang; Chen, Bo; Gong, Yan; Cao, Jianlin; Lin, Jingquan; Lee, Hongyan

2001-12-01

We have been developing a debris-free laser plasma light source with a gas-puff target system whose nozzle is driven by a piezoelectric crystal membrane. The gas-puff target system can utilize gases such as CO2, O2 or some gas mixture according to different experiments. Therefore, in comparison with soft X-ray source using a metal target, after continuously several-hour laser interaction with gas from the gas-puff target system, no evidences show that the light source can produce debris. The debris-free soft X-ray source is prepared for soft X-ray projection lithography research at State Key Laboratory of Applied Optics. Strong emission from CO2, O2 and Kr plasma is observed.

Modular soft x-ray spectrometer for applications in energy sciences and quantum materials

DOE PAGES

Chuang, Yi -De; Shao, Yu -Cheng; Cruz, Alejandro; ...

2017-01-27

Over the past decade, the advances in grating-based soft X-ray spectrometers have revolutionized the soft X-ray spectroscopies in materials research. However, these novel spectrometers are mostly dedicated designs, which cannot be easily adopted for applications with diverging demands. Here we present a versatile spectrometer design concept based on the Hettrick-Underwood optical scheme that uses modular mechanical components. The spectrometer’s optics chamber can be used with gratings operated in either inside or outside orders, and the detector assembly can be reconfigured accordingly. The spectrometer can be designed to have high spectral resolution, exceeding 10 000 resolving power when using small sourcemore » (~1μm) and detector pixels (~5μm) with high line density gratings (~3000 lines/mm), or high throughput at moderate resolution. We report two such spectrometers with slightly different design goals and optical parameters in this paper. We show that the spectrometer with high throughput and large energy window is particularly useful for studying the sustainable energy materials. We demonstrate that the extensive resonant inelastic X-ray scattering (RIXS) map of battery cathode material LiNi 1/3Co 1/3Mn 1/3O 2 can be produced in few hours using such a spectrometer. Unlike analyzing only a handful of RIXS spectra taken at selected excitation photon energies across the elemental absorption edges to determine various spectral features like the localized dd excitations and non-resonant fluorescence emissions, these features can be easily identified in the RIXS maps. Studying such RIXS maps could reveal novel transition metal redox in battery compounds that are sometimes hard to be unambiguously identified in X-ray absorption and emission spectra. As a result, we propose that this modular spectrometer design can serve as the platform for further customization to meet specific scientific demands.« less

Modular soft x-ray spectrometer for applications in energy sciences and quantum materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chuang, Yi -De; Shao, Yu -Cheng; Cruz, Alejandro

Over the past decade, the advances in grating-based soft X-ray spectrometers have revolutionized the soft X-ray spectroscopies in materials research. However, these novel spectrometers are mostly dedicated designs, which cannot be easily adopted for applications with diverging demands. Here we present a versatile spectrometer design concept based on the Hettrick-Underwood optical scheme that uses modular mechanical components. The spectrometer’s optics chamber can be used with gratings operated in either inside or outside orders, and the detector assembly can be reconfigured accordingly. The spectrometer can be designed to have high spectral resolution, exceeding 10 000 resolving power when using small sourcemore » (~1μm) and detector pixels (~5μm) with high line density gratings (~3000 lines/mm), or high throughput at moderate resolution. We report two such spectrometers with slightly different design goals and optical parameters in this paper. We show that the spectrometer with high throughput and large energy window is particularly useful for studying the sustainable energy materials. We demonstrate that the extensive resonant inelastic X-ray scattering (RIXS) map of battery cathode material LiNi 1/3Co 1/3Mn 1/3O 2 can be produced in few hours using such a spectrometer. Unlike analyzing only a handful of RIXS spectra taken at selected excitation photon energies across the elemental absorption edges to determine various spectral features like the localized dd excitations and non-resonant fluorescence emissions, these features can be easily identified in the RIXS maps. Studying such RIXS maps could reveal novel transition metal redox in battery compounds that are sometimes hard to be unambiguously identified in X-ray absorption and emission spectra. As a result, we propose that this modular spectrometer design can serve as the platform for further customization to meet specific scientific demands.« less

Development of In-situ Resonant Soft X-ray Scattering for Soft Materials at Advanced Light Source

NASA Astrophysics Data System (ADS)

Wang, Cheng; Hexemer, Alexander; Young, Anthony; Padmore, Howard

2014-03-01

Resonant Soft X-ray Scattering was developed at ALS over the past a few years. It combines soft x-ray spectroscopy with x-ray scattering and offers statistical information for 3D chemical morphology over a large sample area. Its unique chemical sensitivity, large accessible size scale, polarization control and high coherence make it a powerful tool for mesoscale chemical/morphological structure characterization for many classes of materials. However, in order to study sciences in naturally occurring conditions, we need to overcome the sample limitations set by the low penetration depth of soft x-rays and requirement of high vacuum. Adapting to the evolving environmental cell designs utilized increasingly in the Electron Microscopy community, we will report our development of customize design liquid/gas environmental cells that will enable soft x-ray scattering experiments on biological, electro-chemical, self-assembly, and hierarchical functional systems in both static and dynamic fashion. Initial RSoXS result of solar fuel membrane assembly/fuel-cell membrane structure in wet cell will be presented.

Soft-X-Ray Prefilter for Hot, Bright Objects

NASA Technical Reports Server (NTRS)

Davis, J. M.; Ortendahl, J. A.

1985-01-01

Prefilters consisting of beryllium foil supported on conductive silver mesh transmit soft x-rays but are nearly opaque to visible and infrared light. New Be/AG filters protect imaging X-ray detectors from damage by visible and longer wavelength radiation when viewing such hot, bright emitters as Sun or possibly certain industrial processes.

Soft x-ray reduction camera for submicron lithography

DOEpatents

Hawryluk, Andrew M.; Seppala, Lynn G.

1991-01-01

Soft x-ray projection lithography can be performed using x-ray optical components and spherical imaging lenses (mirrors), which form an x-ray reduction camera. The x-ray reduction is capable of projecting a 5x demagnified image of a mask onto a resist coated wafer using 4.5 nm radiation. The diffraction limited resolution of this design is about 135 nm with a depth of field of about 2.8 microns and a field of view of 0.2 cm.sup.2. X-ray reflecting masks (patterned x-ray multilayer mirrors) which are fabricated on thick substrates and can be made relatively distortion free are used, with a laser produced plasma for the source. Higher resolution and/or larger areas are possible by varying the optic figures of the components and source characteristics.

Precision mechanical structure of an ultra-high-resolution spectrometer for inelastic X-ray scattering instrument

DOEpatents

Shu, Deming; Shvydko, Yuri; Stoupin, Stanislav A.; Khachatryan, Ruben; Goetze, Kurt A.; Roberts, Timothy

2015-04-14

A method and an ultrahigh-resolution spectrometer including a precision mechanical structure for positioning inelastic X-ray scattering optics are provided. The spectrometer includes an X-ray monochromator and an X-ray analyzer, each including X-ray optics of a collimating (C) crystal, a pair of dispersing (D) element crystals, anomalous transmission filter (F) and a wavelength (W) selector crystal. A respective precision mechanical structure is provided with the X-ray monochromator and the X-ray analyzer. The precision mechanical structure includes a base plate, such as an aluminum base plate; positioning stages for D-crystal alignment; positioning stages with an incline sensor for C/F/W-crystal alignment, and the positioning stages including flexure-based high-stiffness structure.

Soft X-ray Absorption Edges in LMXBs

NASA Technical Reports Server (NTRS)

2004-01-01

The XMM observation of LMC X-2 is part of our program to study X-ray absorption in the interstellar medium (ISM). This program includes a variety of bright X-ray binaries in the Galaxy as well as the Magellanic Clouds (LMC and SMC). LMC X-2 is located near the heart of the LMC. Its very soft X-ray spectrum is used to determine abundance and ionization fractions of neutral and lowly ionized oxygen of the ISM in the LMC. The RGS spectrum so far allowed us to determine the O-edge value to be for atomic O, the EW of O-I in the ls-2p resonance absorption line, and the same for O-II. The current study is still ongoing in conjunction with other low absorption sources like Sco X-1 and the recently observed X-ray binary 4U 1957+11.

Higher-harmonics suppressor for soft x rays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Waki, I.; Hirai, Y.; Momose, A.

We have developed an apparatus for suppressing higher harmonics contained in the soft x-ray output beam of grazing-incidence grating monochromators. It consists of eight pairs of total-reflection mirrors. Each pair serves as a low-pass filter with the cutoff energy different from one another. The eight pairs are designed to cover an energy range of 80--1600 eV with an efficiency of harmonic suppression better than 97%, while transmitting more than 50% of the fundamental photons. We have tested its preliminary performance on the soft x-ray beamline BL-8A at the Photon Factory. We present the observed transmission efficiencies and the effects ofmore » the harmonic suppressor on measurements of reflectivity and fluorescence spectra.« less

Soft x-ray reduction camera for submicron lithography

DOEpatents

Hawryluk, A.M.; Seppala, L.G.

1991-03-26

Soft x-ray projection lithography can be performed using x-ray optical components and spherical imaging lenses (mirrors), which form an x-ray reduction camera. The x-ray reduction is capable of projecting a 5x demagnified image of a mask onto a resist coated wafer using 4.5 nm radiation. The diffraction limited resolution of this design is about 135 nm with a depth of field of about 2.8 microns and a field of view of 0.2 cm[sup 2]. X-ray reflecting masks (patterned x-ray multilayer mirrors) which are fabricated on thick substrates and can be made relatively distortion free are used, with a laser produced plasma for the source. Higher resolution and/or larger areas are possible by varying the optic figures of the components and source characteristics. 9 figures.

The Diffuse Soft X-ray Background: Trials and Tribulations

NASA Astrophysics Data System (ADS)

Ulmer, Melville P.

2013-01-01

I joined the University of Wisconsin-Madison sounding rocket group at its inception. It was an exciting time, as nobody knew what the X-ray sky looked like. Our group focused on the soft X-ray background, and built proportional counters with super thin (2 micron thick) windows. As the inter gas pressure of the counters was about 1 atmosphere, it was no mean feat to get payload to launch without the window bursting. On top of that we built all our own software from space solutions to unfolding the spectral data. For we did it then as now: Our computer code modeled the detector response and then folded various spectral shapes through the response and compared the results with the raw data. As far as interpretation goes, here are examples of how one can get things wrong: The Berkeley group published a paper of the soft X-ray background that disagreed with ours. Why? It turned out they had **assumed** the galactic plane was completely opaque to soft X-ray and hence corrected for detector background that way. It turns out that the ISM emits in soft X-rays! Another example was the faux pas of the Calgary group. They didn’t properly shield their detector from the sounding rocket telemetry. Thus they got an enormous signal, which to our amusement some (ambulance chaser) theoreticians tried to explain! So back then as now, mistakes were made, but at least we all knew how our X-ray systems worked from soup (the detectors) to nuts (the data analysis code) where as toady “anybody” with a good idea but only a vague inkling of how detectors, mirrors and software work, can be an X-ray astronomer. On the one hand, this has made the field accessible to all, and on the other, errors in interpretation can be made as the X-ray telescope user can fall prey to running black box software. Furthermore with so much funding going into supporting observers, there is little left to make the necessary technology advances or keep the core expertise in place to even to stay even with

Resolving the Origin of the Diffuse Soft X-ray Background

NASA Technical Reports Server (NTRS)

Smith, Randall K.; Foster, Adam R.; Edgar, Ricard J.; Brickhouse, Nancy S.; Sanders, Wilton T.

2012-01-01

In January 1993, the Diffuse X-ray Spectrometer (DXS) measured the first high-resolution spectrum of the diffuse soft X-ray background between 44-80A. A line-dominated spectrum characteristic of a 10(exp 6)K collisionally ionized plasma' was expected but while the observed spectrum was clearly line-dominated, no model would fit. Then in 2003 the Cosmic Hot Interstellar Plasma Spectrometer (CHIPS) launched and observed the diffuse extreme-ultraviolet (EUV) spectrum between 90- 265A. Although many emission lines were again expected; only Fe IX at 171.1A was detected. The discovery of X-rays from comets led to the realization that heavy ions (Z=6-28) in the solar wind will emit soft X-rays as the ions interact via charge exchange with neutral atoms in the heliosphere and geocorona. Using a new model for solar wind charge exchange (SWCX) emission, we show that the diffuse soft X-ray background can be understood as a combination of emission from charge exchange onto the slow and fast solar wind together with a more distant and diffuse hot (10(exp 6)K) plasma.

Depth-resolved electronic structure of spintronic nanostructures and complex materials with soft and hard x-ray photoemission

NASA Astrophysics Data System (ADS)

Gray, Alexander

In this dissertation we describe several new directions in the field of x-ray photoelectron spectroscopy, with a particular focus on the enhancement and control of the depth sensitivity and selectivity of the measurement. Enhancement of the depth sensitivity is achieved by going to higher photon energies with hard x-ray excitation and taking advantage of the resulting larger electron inelastic mean-free paths. This novel approach provides a more accurate picture of bulk electronic structure, when compared to the traditional soft x-ray photoelectron spectroscopy (XPS) which, for some systems, may be too strongly influenced by surface effects. We present three case-studies wherein such hard x-ray photoelectron spectroscopy (HAXPES) in the multi-keV regime is used to probe the bulk properties of complex thin-film materials, which would be otherwise impossible to investigate using conventional soft x-ray XPS. Namely, (1) we directly observe the opening of a semiconducting gap in epitaxial Cr0.80Al0.20 alloy thin films and confirm this with theory, (2) we study the electronic and structural properties of near-Heusler FexSi1-x alloy thin films of various composition and degrees of crystallinity, and (3) we observe the Mott metal-to-insulator transition in the ultra-thin epitaxial LaNiO3 films via core-level and valence-band spectroscopies. By performing the experiments at the photon energy of 5.95 keV, the bulk-sensitivity of the measurements, characterized by the inelastic mean-free path of the photoemitted electrons, is enhanced by a factor of 4--7 compared to the conventional soft x-ray photoelectron spectroscopy. The experimental results are compared to calculations performed using various first-principle theoretical approaches, such as the density-functional theory and the one-step theory of photoemission. Furthermore, we present the first results of hard x-ray angle-resolved photoemission measurements (HARPES), at excitation energies of 3.24 and 5.95 keV. In a

New developments in fabrication of high-energy-resolution analyzers for inelastic x-ray spectroscopy.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Said, A. H.; Sinn, H.; Divan, R.

2011-05-01

In this work new improvements related to the fabrication of spherical bent analyzers for 1 meV energy-resolution inelastic X-ray scattering spectroscopy are presented. The new method includes the use of a two-dimensional bender to achieve the required radius of curvature for X-ray analyzers. The advantage of this method is the ability to monitor the focus during bending, which leads to higher-efficiency analyzers.

The Astro-H High Resolution Soft X-Ray Spectrometer

NASA Technical Reports Server (NTRS)

Kelley, Richard L.; Akamatsu, Hiroki; Azzarell, Phillip; Bialas, Tom; Boyce, Kevin R.; Brown, Gregory V.; Canavan, Edgar; Chiao, Meng P.; Costantini, Elisa; DiPirro, Michael J.;

The Astro-H high resolution soft x-ray spectrometer

NASA Astrophysics Data System (ADS)

Kelley, Richard L.; Akamatsu, Hiroki; Azzarello, Phillipp; Bialas, Tom; Boyce, Kevin R.; Brown, Gregory V.; Canavan, Edgar; Chiao, Meng P.; Costantini, Elisa; DiPirro, Michael J.; Eckart, Megan E.; Ezoe, Yuichiro; Fujimoto, Ryuichi; Haas, Daniel; den Herder, Jan-Willem; Hoshino, Akio; Ishikawa, Kumi; Ishisaki, Yoshitaka; Iyomoto, Naoko; Kilbourne, Caroline A.; Kimball, Mark O.; Kitamoto, Shunji; Konami, Saori; Koyama, Shu; Leutenegger, Maurice A.; McCammon, Dan; Mitsuda, Kazuhisa; Mitsuishi, Ikuyuki; Moseley, Harvey; Murakami, Hiroshi; Murakami, Masahide; Noda, Hirofumi; Ogawa, Mina; Ohashi, Takaya; Okamoto, Atsushi; Ota, Naomi; Paltani, Stéphane; Porter, F. S.; Sakai, Kazuhiro; Sato, Kosuke; Sato, Yohichi; Sawada, Makoto; Seta, Hiromi; Shinozaki, Keisuke; Shirron, Peter J.; Sneiderman, Gary A.; Sugita, Hiroyuki; Szymkowiak, Andrew E.; Takei, Yoh; Tamagawa, Toru; Tashiro, Makoto; Terada, Yukikatsu; Tsujimoto, Masahiro; de Vries, Cor P.; Yamada, Shinya; Yamasaki, Noriko Y.; Yatsu, Yoichi

2016-07-01

We present the overall design and performance of the Astro-H (Hitomi) Soft X-Ray Spectrometer (SXS). The instrument uses a 36-pixel array of x-ray microcalorimeters at the focus of a grazing-incidence x-ray mirror Soft X-Ray Telescope (SXT) for high-resolution spectroscopy of celestial x-ray sources. The instrument was designed to achieve an energy resolution better than 7 eV over the 0.3-12 keV energy range and operate for more than 3 years in orbit. The actual energy resolution of the instrument is 4-5 eV as demonstrated during extensive ground testing prior to launch and in orbit. The measured mass flow rate of the liquid helium cryogen and initial fill level at launch predict a lifetime of more than 4 years assuming steady mechanical cooler performance. Cryogen-free operation was successfully demonstrated prior to launch. The successful operation of the SXS in orbit, including the first observations of the velocity structure of the Perseus cluster of galaxies, demonstrates the viability and power of this technology as a tool for astrophysics.

Single-pulse coherent diffraction imaging using soft x-ray laser.

PubMed

Kang, Hyon Chol; Kim, Hyung Taek; Kim, Sang Soo; Kim, Chan; Yu, Tae Jun; Lee, Seong Ku; Kim, Chul Min; Kim, I Jong; Sung, Jae Hee; Janulewicz, Karol A; Lee, Jongmin; Noh, Do Young

2012-05-15

We report a coherent diffraction imaging (CDI) using a single 8 ps soft x-ray laser pulse at a wavelength of 13.9 nm. The soft x-ray pulse was generated by a laboratory-scale intense pumping laser providing coherent x-ray pulses up to the level of 10(11) photons/pulse. A spatial resolution below 194 nm was achieved with a single pulse, and it was shown that a resolution below 55 nm is feasible with improved detector capability. The single-pulse CDI might provide a way to investigate dynamics of nanoscale molecules or particles.

An extreme ultraviolet telescope with no soft X-ray response

NASA Technical Reports Server (NTRS)

Finley, David S.; Jelinsky, Patrick; Bowyer, Stuart; Malina, Roger F.

1986-01-01

While EUV grazing incidence telescopes of conventional design exhibit a substantial X-ray response as well as an extreme UV response, and existing bandpass filters for the transmission of radiation longward of 400 A also transmit soft X-rays, the grazing incidence telescope presented suppresses this soft X-ray throughput through the incorporation of a Wolter Schwarzschild Type II mirror with large graze angles. The desirable features of an EUV photometric survey telescope are retained. An instrument of this design will be flown on the EUE mission, in order to make a survey of the sky at wavelengths longer than 400 A.

X-ray variability of Cygnus X-1 in its soft state

NASA Technical Reports Server (NTRS)

Cui, W.; Zhang, S. N.; Jahoda, K.; Focke, W.; Swank, J.; Heindl, W. A.; Rothschild, R. E.

1997-01-01

Observations from the Rossi X-ray Timing Explorer (RXTE) of Cyg X-1 in the soft state and during the soft to hard transition are examined. The results of this analysis confirm previous conclusions that for this source there is a settling period (following the transition from the hard to soft state during which the low energy spectrum varies significantly, while the high energy portion changes little) during which the source reaches nominal soft state brightness. This behavior can be characterized by a soft low energy spectrum and significant low frequency 1/f noise and white noise on the power density spectrum, which becomes softer upon reaching the true soft state. The low frequency 1/f noise is not observed when Cyg X-1 is in the hard state, and therefore appears to be positively correlated with the disk mass accretion rate. The difference in the observed spectral and timing properties between the hard and soft states is qualitatively consistent with a fluctuating corona model.

Assessment of surface roughness by use of soft x-ray scattering

NASA Astrophysics Data System (ADS)

Meng, Yan-li; Wang, Yong-gang; Chen, Shu-yan; Chen, Bo

2009-08-01

A soft x-ray reflectometer with laser produced plasma source has been designed, which can work from wavelength 8nm to 30 nm and has high performance. Using the soft x-ray reflectometer above, the scattering light distribution of silicon and zerodur mirrors which have super-smooth surfaces could be measured at different incidence angle and different wavelength. The measurement when the incidence angle is 2 degree and the wavelength is 11nm has been given in this paper. A surface scattering theory of soft x-ray grazing incidence optics based on linear system theory and an inverse scattering mathematical model is introduced. The vector scattering theory of soft x-ray scattering also is stated in detail. The scattering data are analyzed by both the methods above respectively to give information about the surface profiles. On the other hand, both the two samples are measured by WYKO surface profiler, and the surface roughness of the silicon and zerodur mirror is 1.3 nm and 1.5nm respectively. The calculated results are in quantitative agreement with those measured by WYKO surface profiler, which indicates that soft x-ray scattering is a very useful tool for the evaluation of highly polished surfaces. But there still some difference among the results of different theory and WYKO, and the possible reasons of such difference have been discussed in detail.

A hard X-ray view of the soft excess in AGN

NASA Astrophysics Data System (ADS)

Boissay, R.; Ricci, C.; Paltani, S.

2017-10-01

A soft X-ray emission in excess of the extrapolation of the hard X-ray continuum is detected in many Seyfert 1 galaxies below 1 keV. To understand the uncertain nature of this soft excess, which could be due to warm Comptonization or to blurred ionized reflection, we consider the different behaviors of these models above 10 keV. We present the results of a study done on 102 Seyfert 1s from the Swift BAT 70-Month Hard X-ray Survey catalog. We have performed the joint spectral analysis of Swift/BAT and XMM-Newton data in order to get a hard X-ray view of the soft excess. We discuss the links between the soft-excess strength and the reflection at high energy, the slope of the continuum and the Eddington ratio. We compare our results to simulations of blurred ionized-reflection models and show that they are in contradiction. Indeed, we do not find the expected correlation between the reflection and the soft-excess strengths, neither in individual, nor in stacked spectra. We also present our current project of broadband fitting, using different models explaining the soft excess, to simultaneous XMM-Newton and NuSTAR observations of about ten objects of our sample.

[Experimental investigation of laser plasma soft X-ray source with gas target].

PubMed

Ni, Qi-liang; Gong, Yan; Lin, Jing-quan; Chen, Bo; Cao, Jian-lin

2003-02-01

This paper describes a debris-free laser plasma soft X-ray source with a gas target, which has high operating frequency and can produce strong soft X-ray radiation. The valve of this light source is drived by a piezoelectrical ceramic whose operating frequency is up to 400 Hz. In comparison with laser plasma soft X-ray sources using metal target, the light source is debris-free. And it has higher operating frequency than gas target soft X-ray sources whose nozzle is controlled by a solenoid valve. A channel electron multiplier (CEM) operating in analog mode is used to detect the soft X-ray generated by the laser plasma source, and the CEM's output is fed to to a charge-sensitive preamplifier for further amplification purpose. Output charges from the CEM are proportional to the amplitude of the preamplifier's output voltage. Spectra of CO2, Xe and Kr at 8-14 nm wavelength which can be used for soft X-ray projection lithography are measured. The spectrum for CO2 consists of separate spectral lines originate mainly from the transitions in Li-like and Be-like ions. The Xe spectrum originating mainly from 4d-5f, 4d-4f, 4d-6p and 4d-5p transitions in multiply charged xenon ions. The spectrum for Kr consists of separate spectral lines and continuous broad spectra originating mainly from the transitions in Cu-, Ni-, Co- and Fe-like ions.

A von Hamos x-ray spectrometer based on a segmented-type diffraction crystal for single-shot x-ray emission spectroscopy and time-resolved resonant inelastic x-ray scattering studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Szlachetko, J.; Institute of Physics, Jan Kochanowski University, 25-406 Kielce; Nachtegaal, M.

2012-10-15

We report on the design and performance of a wavelength-dispersive type spectrometer based on the von Hamos geometry. The spectrometer is equipped with a segmented-type crystal for x-ray diffraction and provides an energy resolution in the order of 0.25 eV and 1 eV over an energy range of 8000 eV-9600 eV. The use of a segmented crystal results in a simple and straightforward crystal preparation that allows to preserve the spectrometer resolution and spectrometer efficiency. Application of the spectrometer for time-resolved resonant inelastic x-ray scattering and single-shot x-ray emission spectroscopy is demonstrated.

The Elusive Soft Emission from Hard X-ray Symbiotic System RT Cru

NASA Astrophysics Data System (ADS)

Karovska, Margarita

2014-09-01

RT Cru is a fascinating member of a new class of hard X-ray emitting symbiotic binaries showing X-ray emission extending to over 50keV. While its hard X-ray emission has been studied in detail, the soft component of the spectrum, including flares, remains elusive, since previous observations have focused on the high-energy regime. We propose Chandra HRC-S/LETG observations to determine the spatial, spectral, and temporal characteristics of the source of the soft X-ray emission with a goal to establish the origin of the soft component, and determine whether and how it is tied to the hard component. Determining the origin of the soft emission is a crucial piece of the puzzle to understanding the geometry, energetics, and the environment of WD accretion in this class of symbiotic systems.

REDSoX: Monte-Carlo ray-tracing for a soft x-ray spectroscopy polarimeter

NASA Astrophysics Data System (ADS)

Günther, Hans M.; Egan, Mark; Heilmann, Ralf K.; Heine, Sarah N. T.; Hellickson, Tim; Frost, Jason; Marshall, Herman L.; Schulz, Norbert S.; Theriault-Shay, Adam

2017-08-01

X-ray polarimetry offers a new window into the high-energy universe, yet there has been no instrument so far that could measure the polarization of soft X-rays (about 17-80 Å) from astrophysical sources. The Rocket Experiment Demonstration of a Soft X-ray Polarimeter (REDSoX Polarimeter) is a proposed sounding rocket experiment that uses a focusing optic and splits the beam into three channels. Each channel has a set of criticalangle transmission (CAT) gratings that disperse the x-rays onto a laterally graded multilayer (LGML) mirror, which preferentially reflects photons with a specific polarization angle. The three channels are oriented at 120 deg to each other and thus measure the three Stokes parameters: I, Q, and U. The period of the LGML changes with position. The main design challenge is to arrange the gratings so that they disperse the spectrum in such a way that all rays are dispersed onto the position on the multi-layer mirror where they satisfy the local Bragg condition despite arriving on the mirror at different angles due to the converging beam from the focusing optics. We present a polarimeteric Monte-Carlo ray-trace of this design to assess non-ideal effects from e.g. mirror scattering or the finite size of the grating facets. With mirror properties both simulated and measured in the lab for LGML mirrors of 80-200 layers we show that the reflectivity and the width of the Bragg-peak are sufficient to make this design work when non-ideal effects are included in the simulation. Our simulations give us an effective area curve, the modulation factor and the figure of merit for the REDSoX polarimeter. As an example, we simulate an observation of Mk 421 and show that we could easily detect a 20% linear polarization.

Quantifying covalent interactions with resonant inelastic soft X-ray scattering: Case study of Ni 2+ aqua complex

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kunnus, K.; Josefsson, I.; Schreck, S.

We analyze the effects of covalent interactions in Ni 2p3d resonant inelastic X-ray scattering (RIXS) spectra from aqueous Ni 2+ ions and find that the relative RIXS intensities of ligand-to-metal charge-transfer final states with respect to the ligand-field final states reflect the covalent mixing between Ni 3d and water orbitals. Specifically, the experimental intensity ratio at the Ni L 3-edge allows to determine that the Ni 3d orbitals have on average 5.5% of water character. Here, we propose that 2p3d RIXS at the Ni L 3-edge can be utilized to quantify covalency in Ni complexes without the use of externalmore » references or simulations.« less

Quantifying covalent interactions with resonant inelastic soft X-ray scattering: Case study of Ni 2+ aqua complex

DOE PAGES

Kunnus, K.; Josefsson, I.; Schreck, S.; ...

2016-12-23

We analyze the effects of covalent interactions in Ni 2p3d resonant inelastic X-ray scattering (RIXS) spectra from aqueous Ni 2+ ions and find that the relative RIXS intensities of ligand-to-metal charge-transfer final states with respect to the ligand-field final states reflect the covalent mixing between Ni 3d and water orbitals. Specifically, the experimental intensity ratio at the Ni L 3-edge allows to determine that the Ni 3d orbitals have on average 5.5% of water character. Here, we propose that 2p3d RIXS at the Ni L 3-edge can be utilized to quantify covalency in Ni complexes without the use of externalmore » references or simulations.« less

Rapid soft X-ray fluctuations in solar flares observed with the X-ray polychromator

NASA Technical Reports Server (NTRS)

Zarro, D. M.; Saba, J. L. R.; Strong, K. T.

1986-01-01

Three flares observed by the Soft X-Ray Polychromator on the Solar Maximum Mission were studied. Flare light curves from the Flat Crystal Spectrometer and Bent Crystal Spectrometer were examined for rapid signal variations. Each flare was characterized by an initial fast (less than 1 min) burst, observed by the Hard X-Ray Burst Spectrometer (HXRBS), followed by softer gradual X-ray emission lasting several minutes. From an autocorrelation function analysis, evidence was found for quasi-periodic fluctuations with rise and decay times of 10 s in the Ca XIX and Fe XXV light curves. These variations were of small amplitude (less than 20%), often coincided with hard X-ray emissions, and were prominent during the onset of the gradual phase after the initial hard X-ray burst. It is speculated that these fluctuations were caused by repeated energy injections in a coronal loop that had already been heated and filled with dense plasma associated with the initial hard X-ray burst.

Soft X-ray observations of Centaurus X-3 from Copernicus

NASA Technical Reports Server (NTRS)

Margon, B.; Mason, K. O.; Hawkins, F. J.; Sanford, P. W.

1975-01-01

We have detected soft X-ray emission from Centaurus X-3 in the 0.6-1.9 keV band, using the focusing telescope aboard OAO Copernicus. The flux is compatible with an extrapolation of the harder X-ray spectrum, attenuated by (3-4) times 10 to the 22nd atoms per sq cm of interstellar and/or circumstellar matter. The data are consistent with the distance estimate of 5-10 kpc derived from the spectroscopic modulus of the optical component, and obviate the need to postulate the primary to be an anomalously subluminous hot star. There is currently no compelling evidence that such models must be invoked to explain any of the observed compact X-ray sources.

Ground Laboratory Soft X-Ray Durability Evaluation of Aluminized Teflon FEP Thermal Control Insulation

NASA Technical Reports Server (NTRS)

Banks, Bruce A.; deGroh, Kim K.; Stueber, Thomas J.; Sechkar, Edward A.

1998-01-01

Metallized Teflon fluorinated ethylene propylene (FEP) thermal control insulation is mechanically degraded if exposed to a sufficient fluence of soft x-ray radiation. Soft x-ray photons (4-8 A in wavelength or 1.55 - 3.2 keV) emitted during solar flares have been proposed as a cause of mechanical properties degradation of aluminized Teflon FEP thermal control insulation on the Hubble Space Telescope (HST). Such degradation can be characterized by a reduction in elongation-to-failure of the Teflon FER Ground laboratory soft x-ray exposure tests of aluminized Teflon FEP were conducted to assess the degree of elongation degradation which would occur as a result of exposure to soft x-rays in the range of 3-10 keV. Tests results indicate that soft x-ray exposure in the 3-10 keV range, at mission fluence levels, does not alone cause the observed reduction in elongation of flight retrieved samples. The soft x-ray exposure facility design, mechanical properties degradation results and implications will be presented.

Soft x-ray transmission grating spectrometer for X-ray Surveyor and smaller missions with high resolving power

NASA Astrophysics Data System (ADS)

Heilmann, Ralf K.; Bruccoleri, Alexander; Schattenburg, Mark; Kolodziejczak, jeffery; Gaskin, Jessica; O'Dell, Stephen L.

2017-01-01

A number of high priority subjects in astrophysics are addressed by a state-of-the-art soft x-ray grating spectrometer, e.g. the role of Active Galactic Nuclei in galaxy and star formation, characterization of the WHIM and the “missing baryon” problem, characterization of halos around the Milky Way and nearby galaxies, and stellar coronae and surrounding winds and disks. An Explorer-scale, large-area (A > 1,000 cm2), high resolving power (R > 3,000) soft x-ray grating spectrometer is highly feasible based on Critical-Angle Transmission (CAT) grating technology, even for telescopes with angular resolution of 5-10 arcsec. Significantly higher performance could be provided by a CAT grating spectrometer on an X-ray-Surveyor-type mission (A > 4,000 cm2, R > 5,000). CAT gratings combine advantages of blazed reflection gratings (high efficiency, use of higher orders) with those of transmission gratings (low mass, relaxed alignment tolerances and temperature requirements, transparent at higher energies) with minimal mission resource requirements. Blazing is achieved through grazing-incidence reflection off the smooth silicon grating bar sidewalls. Silicon is well matched to the soft x-ray band, and 30% absolute diffraction efficiency has been acheived with clear paths for further improvement. CAT gratings with sidewalls made of high-Z elements allow extension of blazing to higher energies and larger dispersion angles, enabling higher resolving power at shorter wavelengths. X-ray data from CAT gratings coated with a thin layer of platinum using atomic layer deposition demonstrate efficient blazing to higher energies and much larger blaze angles than possible with silicon alone. Measurements of the resolving power of a breadboard CAT grating spectrometer consisting of a Wolter-I slumped-glass focusing optic from GSFC and CAT gratings, taken at the MSFC Stray Light Facility, have demonstrated resolving power > 10,000. Thus currently fabricated CAT gratings are compatible

A multiwavelength study of the Eridanus soft X-ray enhancement

NASA Technical Reports Server (NTRS)

Burrows, D. N.; Singh, K. P.; Nousek, J. A.; Garmire, G. P.; Good, J.

1993-01-01

We present soft X-ray, N(H), and IR maps of the Eridanus soft X-ray enhancement. Soft X-ray maps from the HEAO 1 A-2 LED experiment, processed with a maximum entropy method (MEM) algorithm, show that the enhancement consists of two distinct components: a large hook-shaped component and a small circular component at different temperatures. Both of these are located in 'holes' in the IR emission, and they correspond to N(H) features at very different velocities. The dust surrounding the X-ray enhancements appears to be associated with several high-latitude molecular clouds, which allow us to obtain a probable distance of about 130 pc to the near edge of the main enhancement. The total power emitted by the hot gas is then about 10 exp 35 to 10 exp 36 ergs/s. We consider alternative interpretations of these objects as adiabatic supernova remnants or as stellar wind bubbles and conclude that they are more likely to be stellar wind bubbles, possibly reheated by a SN explosion in the case of the main, hook-shaped object.

Raman and fluorescence contributions to the resonant inelastic soft x-ray scattering on LaAlO3/SrTiO3 heterostructures

NASA Astrophysics Data System (ADS)

Pfaff, F.; Fujiwara, H.; Berner, G.; Yamasaki, A.; Niwa, H.; Kiuchi, H.; Gloskovskii, A.; Drube, W.; Gabel, J.; Kirilmaz, O.; Sekiyama, A.; Miyawaki, J.; Harada, Y.; Suga, S.; Sing, M.; Claessen, R.

2018-01-01

We present a detailed study of the Ti 3 d carriers at the interface of LaAlO3/SrTiO3 heterostructures by high-resolution resonant inelastic soft x-ray scattering (RIXS), with special focus on the roles of overlayer thickness and oxygen vacancies. Our measurements show the existence of interfacial Ti 3 d electrons already below the critical thickness for conductivity. The (total) interface charge carrier density increases up to a LaAlO3 overlayer thickness of 6 unit cells before it levels out. Furthermore, we observe strong Ti 3 d charge carrier doping by oxygen vacancies. The RIXS data combined with photoelectron spectroscopy and transport measurements indicate the simultaneous presence of localized and itinerant charge carriers. At variance with previous interpretations, we show that in our excitation energy dependent RIXS measurements the amounts of localized and itinerant Ti 3 d electrons in the ground state do not scale with the intensities of the Raman and fluorescence peaks, respectively. Rather, we attribute the observation of either Raman components or fluorescence signal to the specific nature of the intermediate state reached in the RIXS excitation process.

Soft X-ray Emission from Large-Scale Galactic Outflows in Seyfert Galaxies

NASA Astrophysics Data System (ADS)

Colbert, E. J. M.; Baum, S.; O'Dea, C.; Veilleux, S.

1998-01-01

Kiloparsec-scale soft X-ray nebulae extend along the galaxy minor axes in several Seyfert galaxies, including NGC 2992, NGC 4388 and NGC 5506. In these three galaxies, the extended X-ray emission observed in ROSAT HRI images has 0.2-2.4 keV X-ray luminosities of 0.4-3.5 x 10(40) erg s(-1) . The X-ray nebulae are roughly co-spatial with the large-scale radio emission, suggesting that both are produced by large-scale galactic outflows. Assuming pressure balance between the radio and X-ray plasmas, the X-ray filling factor is >~ 10(4) times as large as the radio plasma filling factor, suggesting that large-scale outflows in Seyfert galaxies are predominantly winds of thermal X-ray emitting gas. We favor an interpretation in which large-scale outflows originate as AGN-driven jets that entrain and heat gas on kpc scales as they make their way out of the galaxy. AGN- and starburst-driven winds are also possible explanations if the winds are oriented along the rotation axis of the galaxy disk. Since large-scale outflows are present in at least 50 percent of Seyfert galaxies, the soft X-ray emission from the outflowing gas may, in many cases, explain the ``soft excess" X-ray feature observed below 2 keV in X-ray spectra of many Seyfert 2 galaxies.

Bright circularly polarized soft X-ray high harmonics for X-ray magnetic circular dichroism.

PubMed

Fan, Tingting; Grychtol, Patrik; Knut, Ronny; Hernández-García, Carlos; Hickstein, Daniel D; Zusin, Dmitriy; Gentry, Christian; Dollar, Franklin J; Mancuso, Christopher A; Hogle, Craig W; Kfir, Ofer; Legut, Dominik; Carva, Karel; Ellis, Jennifer L; Dorney, Kevin M; Chen, Cong; Shpyrko, Oleg G; Fullerton, Eric E; Cohen, Oren; Oppeneer, Peter M; Milošević, Dejan B; Becker, Andreas; Jaroń-Becker, Agnieszka A; Popmintchev, Tenio; Murnane, Margaret M; Kapteyn, Henry C

2015-11-17

We demonstrate, to our knowledge, the first bright circularly polarized high-harmonic beams in the soft X-ray region of the electromagnetic spectrum, and use them to implement X-ray magnetic circular dichroism measurements in a tabletop-scale setup. Using counterrotating circularly polarized laser fields at 1.3 and 0.79 µm, we generate circularly polarized harmonics with photon energies exceeding 160 eV. The harmonic spectra emerge as a sequence of closely spaced pairs of left and right circularly polarized peaks, with energies determined by conservation of energy and spin angular momentum. We explain the single-atom and macroscopic physics by identifying the dominant electron quantum trajectories and optimal phase-matching conditions. The first advanced phase-matched propagation simulations for circularly polarized harmonics reveal the influence of the finite phase-matching temporal window on the spectrum, as well as the unique polarization-shaped attosecond pulse train. Finally, we use, to our knowledge, the first tabletop X-ray magnetic circular dichroism measurements at the N4,5 absorption edges of Gd to validate the high degree of circularity, brightness, and stability of this light source. These results demonstrate the feasibility of manipulating the polarization, spectrum, and temporal shape of high harmonics in the soft X-ray region by manipulating the driving laser waveform.

Bright circularly polarized soft X-ray high harmonics for X-ray magnetic circular dichroism

PubMed Central

Fan, Tingting; Grychtol, Patrik; Knut, Ronny; Hernández-García, Carlos; Hickstein, Daniel D.; Zusin, Dmitriy; Gentry, Christian; Dollar, Franklin J.; Mancuso, Christopher A.; Hogle, Craig W.; Kfir, Ofer; Legut, Dominik; Carva, Karel; Ellis, Jennifer L.; Dorney, Kevin M.; Chen, Cong; Shpyrko, Oleg G.; Fullerton, Eric E.; Cohen, Oren; Oppeneer, Peter M.; Milošević, Dejan B.; Becker, Andreas; Jaroń-Becker, Agnieszka A.; Popmintchev, Tenio; Murnane, Margaret M.; Kapteyn, Henry C.

2015-01-01

We demonstrate, to our knowledge, the first bright circularly polarized high-harmonic beams in the soft X-ray region of the electromagnetic spectrum, and use them to implement X-ray magnetic circular dichroism measurements in a tabletop-scale setup. Using counterrotating circularly polarized laser fields at 1.3 and 0.79 µm, we generate circularly polarized harmonics with photon energies exceeding 160 eV. The harmonic spectra emerge as a sequence of closely spaced pairs of left and right circularly polarized peaks, with energies determined by conservation of energy and spin angular momentum. We explain the single-atom and macroscopic physics by identifying the dominant electron quantum trajectories and optimal phase-matching conditions. The first advanced phase-matched propagation simulations for circularly polarized harmonics reveal the influence of the finite phase-matching temporal window on the spectrum, as well as the unique polarization-shaped attosecond pulse train. Finally, we use, to our knowledge, the first tabletop X-ray magnetic circular dichroism measurements at the N4,5 absorption edges of Gd to validate the high degree of circularity, brightness, and stability of this light source. These results demonstrate the feasibility of manipulating the polarization, spectrum, and temporal shape of high harmonics in the soft X-ray region by manipulating the driving laser waveform. PMID:26534992

New developments in ALFT's soft x-ray point sources

NASA Astrophysics Data System (ADS)

Cintron, Dario F.; Guo, Xiaoming; Xu, Meisheng; Ye, Rubin; Antoshko, Yuriy; Antoshko, Yuriy; Drew, Steve; Philippe, Albert; Panarella, Emilio

2002-07-01

The new development in ALFT soft X-ray point source VSX-400 consists mainly of an improvement of the nozzle design to reduce the source size, as well as the introduction of a novel trigger system, capable of triggering the discharge hundreds of million of times without failure, and a debris removal system. Continuous operation for 8 hours at 20 kHz allows us to achieve 400 mW of useful soft X-ray radiation around 1 nm wavelength. In another regime of operation with a high energy machine, the VSX-Z, we have been able to achieve consistently 10 J of X-rays per pulse at a repetition rate that can reach 1 Hz with an input electrical energy of approximately 3 kJ and an efficiency in excess of 10-3.

Disentangling AGN and Star Formation in Soft X-Rays

NASA Technical Reports Server (NTRS)

LaMassa, Stephanie M.; Heckman, T. M.; Ptak, A.

2012-01-01

We have explored the interplay of star formation and active galactic nucleus (AGN) activity in soft X-rays (0.5-2 keV) in two samples of Seyfert 2 galaxies (Sy2s). Using a combination of low-resolution CCD spectra from Chandra and XMM-Newton, we modeled the soft emission of 34 Sy2s using power-law and thermal models. For the 11 sources with high signal-to-noise Chandra imaging of the diffuse host galaxy emission, we estimate the luminosity due to star formation by removing the AGN, fitting the residual emission. The AGN and star formation contributions to the soft X-ray luminosity (i.e., L(sub x,AGN) and L(sub x,SF)) for the remaining 24 Sy2s were estimated from the power-law and thermal luminosities derived from spectral fitting. These luminosities were scaled based on a template derived from XSINGS analysis of normal star-forming galaxies. To account for errors in the luminosities derived from spectral fitting and the spread in the scaling factor, we estimated L(sub x,AGN) and L(sub x,SF))from Monte Carlo simulations. These simulated luminosities agree with L(sub x,AGN) and L(sub x,SF) derived from Chandra imaging analysis within a 3sigma confidence level. Using the infrared [Ne ii]12.8 micron and [O iv]26 micron lines as a proxy of star formation and AGN activity, respectively, we independently disentangle the contributions of these two processes to the total soft X-ray emission. This decomposition generally agrees with L(sub x,SF) and L(sub x,AGN) at the 3 sigma level. In the absence of resolvable nuclear emission, our decomposition method provides a reasonable estimate of emission due to star formation in galaxies hosting type 2 AGNs.

X-ray dense cellular inclusions in the cells of the green alga Chlamydomonas reinhardtii as seen by soft-x-ray microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stead, A.D.; Ford, T.W.; Page, A.M.

1997-04-01

Soft x-rays, having a greater ability to penetrate biological material than electrons, have the potential for producing images of intact, living cells. In addition, by using the so-called {open_quotes}water window{close_quotes} area of the soft x-ray spectrum, a degree of natural contrast is introduced into the image due to differential absorption of the wavelengths by compounds with a high carbon content compared to those with a greater oxygen content. The variation in carbon concentration throughout a cell therefore generates an image which is dependent upon the carbon density within the specimen. Using soft x-ray contact microscopy the authors have previously examinedmore » the green alga Chlamydomonas reinhardtii, and the most prominent feature of the cells are the numerous x-ray absorbing spheres, But they were not seen by conventional transmission electron microscopy. Similar structures have also been reported by the Goettingen group using their cryo transmission x-ray microscope at BESSY. Despite the fact that these spheres appear to occupy up to 20% or more of the cell volume when seen by x-ray microscopy, they are not visible by transmission electron microscopy. Given the difficulties and criticisms associated with soft x-ray contact microscopy, the present study was aimed at confirming the existence of these cellular inclusions and learning more of their possible chemical composition.« less

Model of flare lightcurve profile observed in soft X-rays

NASA Astrophysics Data System (ADS)

Gryciuk, Magdalena; Siarkowski, Marek; Gburek, Szymon; Podgorski, Piotr; Sylwester, Janusz; Kepa, Anna; Mrozek, Tomasz

We propose a new model for description of solar flare lightcurve profile observed in soft X-rays. The method assumes that single-peaked `regular' flares seen in lightcurves can be fitted with the elementary time profile being a convolution of Gaussian and exponential functions. More complex, multi-peaked flares can be decomposed as a sum of elementary profiles. During flare lightcurve fitting process a linear background is determined as well. In our study we allow the background shape over the event to change linearly with time. Presented approach originally was dedicated to the soft X-ray small flares recorded by Polish spectrophotometer SphinX during the phase of very deep solar minimum of activity, between 23 rd and 24 th Solar Cycles. However, the method can and will be used to interpret the lightcurves as obtained by the other soft X-ray broad-band spectrometers at the time of both low and higher solar activity level. In the paper we introduce the model and present examples of fits to SphinX and GOES 1-8 Å channel observations as well.

Solar flare hard and soft x ray relationship determined from SMM HXRBS and BCS data

NASA Technical Reports Server (NTRS)

Toot, G. David

1989-01-01

The exact nature of the solar flare process is still somewhat a mystery. A key element to understanding flares if the relationship between the hard x rays emitted by the most energetic portions of the flare and the soft x rays from other areas and times. This relationship was studied by comparing hard x ray light curved from the Hard X-Ray Burst Spectrometer (HXRBS) with the soft x ray light curve and its derivation from the Bent Crystal Spectrometer (BCS) which is part of the X-Ray Polychrometer (XRP), these instruments being on the Solar Maximum Mission spacecraft (SMM). Data sample was taken from flares observed with the above instruments during 1980, the peak of the previous maximum of solar activity. Flares were chosen based on complete coverage of the event by several instruments. The HXRBS data covers the x ray spectrum from about 25 keV to about 440 keV in 15 spectral channels, while the BCS data used covers a region of the Spectrum around 3 angstroms including emission from the Ca XIX ion. Both sets of data were summed over their spectral ranges and plotted against time at a maximum time resolution of around 3 seconds. The most popular theory of flares holds that a beam of electrons produces the hard x rays by bremsstrahlung while the soft x rays are the thermal response to this energy deposition. The question is whether the rate of change of soft x ray emission might reflect the variability of the electron beam and hence the variability of the hard x rays. To address this, we took the time derivative of the soft x ray light curve and compared it to the hard flares, 12 of them showed very closed agreement between the soft x ray derivative and the hard x ray light curve. The other five did not show this behavior but were similar to each other in general soft x ray behavior. Efforts to determine basic differences between the two kinds of flares continue. In addition the behavior of soft x ray temperature of flares was examined.

Solar flare hard and soft X ray relationship determined from SMM HXRBS and BCS data

NASA Astrophysics Data System (ADS)

Toot, G. David

1989-09-01

The exact nature of the solar flare process is still somewhat a mystery. A key element to understanding flares if the relationship between the hard x rays emitted by the most energetic portions of the flare and the soft x rays from other areas and times. This relationship was studied by comparing hard x ray light curved from the Hard X-Ray Burst Spectrometer (HXRBS) with the soft x ray light curve and its derivation from the Bent Crystal Spectrometer (BCS) which is part of the X-Ray Polychrometer (XRP), these instruments being on the Solar Maximum Mission spacecraft (SMM). Data sample was taken from flares observed with the above instruments during 1980, the peak of the previous maximum of solar activity. Flares were chosen based on complete coverage of the event by several instruments. The HXRBS data covers the x ray spectrum from about 25 keV to about 440 keV in 15 spectral channels, while the BCS data used covers a region of the Spectrum around 3 angstroms including emission from the Ca XIX ion. Both sets of data were summed over their spectral ranges and plotted against time at a maximum time resolution of around 3 seconds. The most popular theory of flares holds that a beam of electrons produces the hard x rays by bremsstrahlung while the soft x rays are the thermal response to this energy deposition. The question is whether the rate of change of soft x ray emission might reflect the variability of the electron beam and hence the variability of the hard x rays. To address this, we took the time derivative of the soft x ray light curve and compared it to the hard flares, 12 of them showed very closed agreement between the soft x ray derivative and the hard x ray light curve. The other five did not show this behavior but were similar to each other in general soft x ray behavior. Efforts to determine basic differences between the two kinds of flares continue. In addition the behavior of soft x ray temperature of flares was examined.

Observing the Magnetosphere in Soft X-Rays: The Lunar X-Ray Observatory (LXO)

NASA Astrophysics Data System (ADS)

Sibeck, D. G.; Collier, M. R.; Porter, F. S.

2018-02-01

Wide field-of-view soft X-ray imagers in lunar orbit or on the lunar surface can be used to address many heliophysics objectives, including the nature of the solar wind magnetosphere-interaction, the lunar exosphere, and the helium focusing cone.

Ground Calibration of the Astro-H (Hitomi) Soft X-Ray Spectrometer

NASA Technical Reports Server (NTRS)

Eckart, M. E.; Adams, J. S.; Boyce, K. R.; Brown, G. V.; Chiao, Meng P.; Fujimoto, R. J.; Haas, D.; Den Herder, J. W.; Ishisaki, Y.; Kelley, R. L.;

The coolest DA white dwarfs detected at soft X-ray wavelengths

NASA Technical Reports Server (NTRS)

Kidder, K. M.; Holberg, J. B.; Barstow, M. A.; Tweedy, R. W.; Wesemael, F.

1992-01-01

New soft X-ray/EUV photometric observations of the DA white dwarfs KPD 0631 + 1043 = WD 0631 + 107 and PG 1113 + 413 = WD 1113 + 413 are analyzed. Previously reported soft X-ray detections of three other DAs and the failure to detect a fourth DA in deep Exosat observations are investigated. New ground-based spectra are presented for all of the objects, with IUE Ly-alpha spectra for some. These data are used to constrain the effective temperatures and surface gravities. The improved estimates of these parameters are employed to refer a photospheric He abundance for the hotter objects and to elucidate an effective observational low-temperature threshold for the detection of pure hydrogen DA white dwarfs at soft X-ray wavelengths.

Soft X-Ray Second Harmonic Generation as an Interfacial Probe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lam, R. K.; Raj, S. L.; Pascal, T. A.

Nonlinear optical processes at soft x-ray wavelengths have remained largely unexplored due to the lack of available light sources with the requisite intensity and coherence. Here we report the observation of soft x-ray second harmonic generation near the carbon K edge (~284 eV) in graphite thin films generated by high intensity, coherent soft x-ray pulses at the FERMI free electron laser. Our experimental results and accompanying first-principles theoretical analysis highlight the effect of resonant enhancement above the carbon K edge and show the technique to be interfacially sensitive in a centrosymmetric sample with second harmonic intensity arising primarily from themore » first atomic layer at the open surface. This technique and the associated theoretical framework demonstrate the ability to selectively probe interfaces, including those that are buried, with elemental specificity, providing a new tool for a range of scientific problems.« less

Soft X-Ray Second Harmonic Generation as an Interfacial Probe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lam, R. K.; Raj, S. L.; Pascal, T. A.

Nonlinear optical processes at soft x-ray wavelengths have remained largely unexplored due to the lack of available light sources with the requisite intensity and coherence. Here we report the observation of soft x-ray second harmonic generation near the carbon K edge (~284 eV) in graphite thin films generated by high intensity, coherent soft x-ray pulses at the FERMI free electron laser. Our experimental results and accompanying first-principles theoretical analysis highlight the effect of resonant enhancement above the carbon K edge and show the technique to be interfacially sensitive in a centrosymmetric sample with second harmonic intensity arising primarily from themore » first atomic layer at the open surface. Here, this technique and the associated theoretical framework demonstrate the ability to selectively probe interfaces, including those that are buried, with elemental specificity, providing a new tool for a range of scientific problems.« less

Soft X-Ray Second Harmonic Generation as an Interfacial Probe

DOE PAGES

Lam, R. K.; Raj, S. L.; Pascal, T. A.; ...

2018-01-08

Nonlinear optical processes at soft x-ray wavelengths have remained largely unexplored due to the lack of available light sources with the requisite intensity and coherence. Here we report the observation of soft x-ray second harmonic generation near the carbon K edge (~284 eV) in graphite thin films generated by high intensity, coherent soft x-ray pulses at the FERMI free electron laser. Our experimental results and accompanying first-principles theoretical analysis highlight the effect of resonant enhancement above the carbon K edge and show the technique to be interfacially sensitive in a centrosymmetric sample with second harmonic intensity arising primarily from themore » first atomic layer at the open surface. Here, this technique and the associated theoretical framework demonstrate the ability to selectively probe interfaces, including those that are buried, with elemental specificity, providing a new tool for a range of scientific problems.« less

Soft X-Ray Second Harmonic Generation as an Interfacial Probe

NASA Astrophysics Data System (ADS)

Lam, R. K.; Raj, S. L.; Pascal, T. A.; Pemmaraju, C. D.; Foglia, L.; Simoncig, A.; Fabris, N.; Miotti, P.; Hull, C. J.; Rizzuto, A. M.; Smith, J. W.; Mincigrucci, R.; Masciovecchio, C.; Gessini, A.; Allaria, E.; De Ninno, G.; Diviacco, B.; Roussel, E.; Spampinati, S.; Penco, G.; Di Mitri, S.; Trovò, M.; Danailov, M.; Christensen, S. T.; Sokaras, D.; Weng, T.-C.; Coreno, M.; Poletto, L.; Drisdell, W. S.; Prendergast, D.; Giannessi, L.; Principi, E.; Nordlund, D.; Saykally, R. J.; Schwartz, C. P.

2018-01-01

Nonlinear optical processes at soft x-ray wavelengths have remained largely unexplored due to the lack of available light sources with the requisite intensity and coherence. Here we report the observation of soft x-ray second harmonic generation near the carbon K edge (˜284 eV ) in graphite thin films generated by high intensity, coherent soft x-ray pulses at the FERMI free electron laser. Our experimental results and accompanying first-principles theoretical analysis highlight the effect of resonant enhancement above the carbon K edge and show the technique to be interfacially sensitive in a centrosymmetric sample with second harmonic intensity arising primarily from the first atomic layer at the open surface. This technique and the associated theoretical framework demonstrate the ability to selectively probe interfaces, including those that are buried, with elemental specificity, providing a new tool for a range of scientific problems.

A soft x-ray octadecyl hydrogen maleate crystal spectrograph

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fan, P.Z.; Fill, E.E.; Tietang, G.

1996-03-01

A crystal spectrograph is described which can be used to investigate laser-produced plasmas in the region of soft x rays at wavelengths of up to 60 A. The spectrograph uses an octadecyl hydrogen maleate crystal with a 2{ital d} of 63.5 A, combined with a very thin carbon filter (3000 A thick). As examples of its application, soft x-ray spectra in the range of 43{endash}51 A from laser plasmas of Si and Cu are presented. A spectral resolution of {lambda}/{Delta}{lambda}=1100 is deduced from the spectra. {copyright} {ital 1996 American Institute of Physics.}

The high-field magnet endstation for X-ray magnetic dichroism experiments at ESRF soft X-ray beamline ID32.

PubMed

Kummer, K; Fondacaro, A; Jimenez, E; Velez-Fort, E; Amorese, A; Aspbury, M; Yakhou-Harris, F; van der Linden, P; Brookes, N B

2016-03-01

A new high-field magnet endstation for X-ray magnetic dichroism experiments has been installed and commissioned at the ESRF soft X-ray beamline ID32. The magnet consists of two split-pairs of superconducting coils which can generate up to 9 T along the beam and up to 4 T orthogonal to the beam. It is connected to a cluster of ultra-high-vacuum chambers that offer a comprehensive set of surface preparation and characterization techniques. The endstation and the beam properties have been designed to provide optimum experimental conditions for X-ray magnetic linear and circular dichroism experiments in the soft X-ray range between 400 and 1600 eV photon energy. User operation started in November 2014.

Soft X-ray spectroscopy of nanoparticles by velocity map imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kostko, O.; Xu, B.; Jacobs, M. I.

Velocity map imaging (VMI), a technique traditionally used to study chemical dynamics in the gas phase, is applied to study X-ray photoemission from aerosol nanoparticles. Soft X-rays from the Advanced Light Source synchrotron, probe a beam of nanoparticles, and the resulting photoelectrons are velocity mapped to obtain their kinetic energy distributions. A new design of the VMI spectrometer is described. The spectrometer is benchmarked by measuring vacuum ultraviolet photoemission from gas phase xenon and squalene nanoparticles followed by measurements using soft X-rays. It is demonstrated that the photoelectron distribution from X-ray irradiated squalene nanoparticles is dominated by secondary electrons. Bymore » scanning the photon energies and measuring the intensities of these secondary electrons, a near edge X-ray absorption fine structure (NEXAFS) spectrum is obtained. The NEXAFS technique is used to obtain spectra of aqueous nanoparticles at the oxygen K edge. By varying the position of the aqueous nanoparticle beam relative to the incident X-ray beam, evidence is presented such that the VMI technique allows for NEXAFS spectroscopy of water in different physical states. Finally, we discuss the possibility of applying VMI methods to probe liquids and solids via X-ray spectroscopy.« less

Soft X-ray spectroscopy of nanoparticles by velocity map imaging

DOE PAGES

Kostko, O.; Xu, B.; Jacobs, M. I.; ...

2017-05-05

Velocity map imaging (VMI), a technique traditionally used to study chemical dynamics in the gas phase, is applied to study X-ray photoemission from aerosol nanoparticles. Soft X-rays from the Advanced Light Source synchrotron, probe a beam of nanoparticles, and the resulting photoelectrons are velocity mapped to obtain their kinetic energy distributions. A new design of the VMI spectrometer is described. The spectrometer is benchmarked by measuring vacuum ultraviolet photoemission from gas phase xenon and squalene nanoparticles followed by measurements using soft X-rays. It is demonstrated that the photoelectron distribution from X-ray irradiated squalene nanoparticles is dominated by secondary electrons. Bymore » scanning the photon energies and measuring the intensities of these secondary electrons, a near edge X-ray absorption fine structure (NEXAFS) spectrum is obtained. The NEXAFS technique is used to obtain spectra of aqueous nanoparticles at the oxygen K edge. By varying the position of the aqueous nanoparticle beam relative to the incident X-ray beam, evidence is presented such that the VMI technique allows for NEXAFS spectroscopy of water in different physical states. Finally, we discuss the possibility of applying VMI methods to probe liquids and solids via X-ray spectroscopy.« less

PSPC soft x-ray observations of Seyfert 2 galaxies

NASA Technical Reports Server (NTRS)

Turner, T. J.; Urry, C. M.; Mushotzky, R. F.

1993-01-01

We present the results from ROSAT PSPC soft x-ray (0.1-2.0 keV) observations of six Seyfert 2 galaxies, chosen from the brightest Seyfert 2s detected with the Einstein Imaging Proportional Counter. All of the targets were detected with the ROSAT PSPC. Spatial analysis shows that the source density within a few arcmin of each Seyfert 2 galaxy is a factor of approximately eight higher than in the rest of the inner field of view of the PSPC images. In NGC1365 it appears that the serendipitous sources may be x-ray binary systems in the host galaxy. The proximity of the serendipitous sources, typically within a few arcmin of the target Seyfert 2, means that previous x-ray observations of the Seyfert 2 galaxies have been significantly contaminated, and that source confusion is important on a spatial scale of approximately 1 arcmin. Some spectra, most notably Mrk3 and NGC1365, indicate the presence of a high equivalent width soft x-ray line blend consistent with unresolved iron L and oxygen K emission.

The superconducting high-resolution soft X-ray spectrometer at the advanced biological and environmental X-ray facility

NASA Astrophysics Data System (ADS)

Friedrich, S.; Drury, O. B.; George, S. J.; Cramer, S. P.

2007-11-01

We have built a 36-pixel superconducting tunnel junction X-ray spectrometer for chemical analysis of dilute samples in the soft X-ray band. It offers an energy resolution of ˜10-20 eV FWHM below 1 keV, a solid angle coverage of ˜10 -3, and can be operated at total rates of up to ˜10 6 counts/s. Here, we describe the spectrometer performance in speciation measurements by fluorescence-detected X-ray absorption spectroscopy at the Advanced Biological and Environmental X-ray facility at the ALS synchrotron.

The Soft X-ray Imager (SXI) on the SMILE Mission

NASA Astrophysics Data System (ADS)

Sembay, S.; Branduardi-Raymont, G.; Drumm, P.; Escoubet, C. P.; Genov, G.; Gow, J.; Hall, D.; Holland, A.; Hudec, R.; Mas-Hesse, J. M.; Kennedy, T.; Kuntz, K. D.; Nakamura, R.; Ostgaard, N.; Ottensamer, R.; Raab, W.; Read, A.; Rebuffat, D.; Romstedt, J.; Schyns, E.; Sibeck, D. G.; Srp, A.; Steller, M.; Sun, T.; Sykes, J. M.; Thornhill, J.; Walsh, B.; Walton, D.; Wang, C.; Wei, F.; Wielders, A.; Whittaker, I. C.

2016-12-01

SMILE (Solar wind Magnetosphere Ionosphere Link Explorer) is a space mission dedicated to study the interaction of the solar wind with the Earth's magnetic field. SMILE will investigate the dynamic response of the Earth's magnetosphere to the impact of the solar wind in a unique manner, never attempted before: it will combine soft X-ray imaging of the Earth's magnetic boundaries and magnetospheric cusps with simultaneous UV imaging of the Northern aurora, while simultaneously providing context measurements via an in situ plasma and magnetometer instrument package. SMILE is a joint European Space Agency (ESA) and Chinese Academy of Sciences (CAS) collaborative mission due for launch in 2021. This talk will describe the Soft X-ray Imager (SXI) on SMILE. The SXI is designed for good detection sensitivity of the soft X-rays (0.2 - 2.0 keV) produced in the Earth's exosphere by the solar wind charge exchange process. This process is the mechanism by which it is possible to globally image the Earth's dayside magnetosheath, magnetopause boundary, bowshock and cusps. The wide field of view of the instrument (27° x 16°) is achieved by the use of a micropore optic (MPO) with a Lobster-eye focusing geometry. The detector consists of two large format CCDs (each 8.1 cm x 6.8 cm sensitive area) providing high quantum efficiency and medium energy resolution for soft X-rays. The instrument design will be presented along with simulation results indicating the instrument sensitivity and science return.

Bright circularly polarized soft X-ray high harmonics for X-ray magnetic circular dichroism

DOE PAGES

Fan, Tingting; Grychtol, Patrik; Knut, Ronny; ...

2015-11-03

Here, we demonstrate, to our knowledge, the first bright circularly polarized high-harmonic beams in the soft X-ray region of the electromagnetic spectrum, and use them to implement X-ray magnetic circular dichroism measurements in a tabletop-scale setup. Using counterrotating circularly polarized laser fields at 1.3 and 0.79 µm, we generate circularly polarized harmonics with photon energies exceeding 160 eV. The harmonic spectra emerge as a sequence of closely spaced pairs of left and right circularly polarized peaks, with energies determined by conservation of energy and spin angular momentum. We explain the single-atom and macroscopic physics by identifying the dominant electron quantummore » trajectories and optimal phase-matching conditions. The first advanced phase-matched propagation simulations for circularly polarized harmonics reveal the influence of the finite phase-matching temporal window on the spectrum, as well as the unique polarization-shaped attosecond pulse train. Finally, we use, to our knowledge, the first tabletop X-ray magnetic circular dichroism measurements at the N 4,5 absorption edges of Gd to validate the high degree of circularity, brightness, and stability of this light source. These results demonstrate the feasibility of manipulating the polarization, spectrum, and temporal shape of high harmonics in the soft X-ray region by manipulating the driving laser waveform.« less

Overview of nanoscale NEXAFS performed with soft X-ray microscopes.

PubMed

Guttmann, Peter; Bittencourt, Carla

2015-01-01

Today, in material science nanoscale structures are becoming more and more important. Not only for the further miniaturization of semiconductor devices like carbon nanotube based transistors, but also for newly developed efficient energy storage devices, gas sensors or catalytic systems nanoscale and functionalized materials have to be analysed. Therefore, analytical tools like near-edge X-ray absorption fine structure (NEXAFS) spectroscopy has to be applied on single nanostructures. Scanning transmission X-ray microscopes (STXM) as well as full-field transmission X-ray microscopes (TXM) allow the required spatial resolution to study individual nanostructures. In the soft X-ray energy range only STXM was used so far for NEXAFS studies. Due to its unique setup, the TXM operated by the Helmholtz-Zentrum Berlin (HZB) at the electron storage ring BESSY II is the first one in the soft X-ray range which can be used for NEXAFS spectroscopy studies which will be shown in this review. Here we will give an overview of the different microscopes used for NEXAFS studies and describe their advantages and disadvantages for different samples.

Variable soft X-ray excesses in active galactic nuclei from nonthermal electron-positron pair cascades

NASA Technical Reports Server (NTRS)

Zdziarski, Andrzej A.; Coppi, Paolo S.

1991-01-01

In the present study of the formation of steep soft X-ray excesses that are superposed on flatter, hard X-ray power-law spectra in nonthermal electron-positron pair cascade sources, the soft excess in pair-cascade AGN models appears as a steep power law superposed on the tail of the UV bump and the flat nonthermal (hard X-ray) power law. The model-parameter space in which an excess in soft X-rays is visible is ascertained, and the time-variability of soft excesses in pair cascade models is examined. It is established that the parameter space in which soft excesses appear encompasses the range of preferred input parameters for a recently development Compton reflection model of UV and X-ray emission from the central engine of an AGN.

Ground Laboratory Soft X-Ray Durability Evaluation of Aluminized Teflon FEP Thermal Control Insulation. Revised

NASA Technical Reports Server (NTRS)

Banks, Bruce A.; deGroh, Kim K.; Stueber, Thomas J.; Sechkar, Edward A.; Hall, Rachelle L.

1998-01-01

Metallized Teflon fluorinated ethylene propylene (FEP) thermal control insulation is mechanically degraded if exposed to a sufficient fluence of soft x-ray radiation. Soft x-ray photons (4-8 A in wavelength or 1.55 - 3.2 keV) emitted during solar flares have been proposed as a cause of mechanical properties degradation of aluminized Teflon FEP thermal control insulation on the Hubble Space Telescope (HST). Such degradation can be characterized by a reduction in elongation-to-failure of the Teflon FEP. Ground laboratory soft x-ray exposure tests of aluminized Teflon FEP were conducted to assess the degree of elongation degradation which would occur as a result of exposure to soft x-rays in the range of 3-10 keV. Tests results indicate that soft x-ray exposure in the 3-10 keV range, at mission fluence levels, does not alone cause the observed reduction in elongation of flight retrieved samples. The soft x-ray exposure facility design, mechanical properties degradation results and implications will be presented.

Dark jets in the soft X-ray state of black hole binaries?

NASA Astrophysics Data System (ADS)

Drappeau, S.; Malzac, J.; Coriat, M.; Rodriguez, J.; Belloni, T. M.; Belmont, R.; Clavel, M.; Chakravorty, S.; Corbel, S.; Ferreira, J.; Gandhi, P.; Henri, G.; Petrucci, P.-O.

2017-04-01

X-ray binary observations led to the interpretation that powerful compact jets, produced in the hard state, are quenched when the source transitions to its soft state. The aim of this paper is to discuss the possibility that a powerful dark jet is still present in the soft state. Using the black hole X-ray binaries GX339-4 and H1743-322 as test cases, we feed observed X-ray power density spectra in the soft state of these two sources to an internal shock jet model. Remarkably, the predicted radio emission is consistent with current upper limits. Our results show that for these two sources, a compact dark jet could persist in the soft state with no major modification of its kinetic power compared to the hard state.

Stimulated Electronic X-Ray Raman Scattering

NASA Astrophysics Data System (ADS)

Weninger, Clemens; Purvis, Michael; Ryan, Duncan; London, Richard A.; Bozek, John D.; Bostedt, Christoph; Graf, Alexander; Brown, Gregory; Rocca, Jorge J.; Rohringer, Nina

2013-12-01

We demonstrate strong stimulated inelastic x-ray scattering by resonantly exciting a dense gas target of neon with femtosecond, high-intensity x-ray pulses from an x-ray free-electron laser (XFEL). A small number of lower energy XFEL seed photons drive an avalanche of stimulated resonant inelastic x-ray scattering processes that amplify the Raman scattering signal by several orders of magnitude until it reaches saturation. Despite the large overall spectral width, the internal spiky structure of the XFEL spectrum determines the energy resolution of the scattering process in a statistical sense. This is demonstrated by observing a stochastic line shift of the inelastically scattered x-ray radiation. In conjunction with statistical methods, XFELs can be used for stimulated resonant inelastic x-ray scattering, with spectral resolution smaller than the natural width of the core-excited, intermediate state.

Soft X-ray streak camera for laser fusion applications

NASA Astrophysics Data System (ADS)

Stradling, G. L.

1981-04-01

The development and significance of the soft x-ray streak camera (SXRSC) in the context of inertial confinement fusion energy development is reviewed as well as laser fusion and laser fusion diagnostics. The SXRSC design criteria, the requirement for a subkilovolt x-ray transmitting window, and the resulting camera design are explained. Theory and design of reflector-filter pair combinations for three subkilovolt channels centered at 220 eV, 460 eV, and 620 eV are also presented. Calibration experiments are explained and data showing a dynamic range of 1000 and a sweep speed of 134 psec/mm are presented. Sensitivity modifications to the soft x-ray streak camera for a high-power target shot are described. A preliminary investigation, using a stepped cathode, of the thickness dependence of the gold photocathode response is discussed. Data from a typical Argus laser gold-disk target experiment are shown.

The soft X-ray polychromator for the Solar Maximum Mission

NASA Technical Reports Server (NTRS)

Acton, L. W.; Finch, M. L.; Gilbreth, C. W.; Culhane, J. L.; Bentley, R. D.; Bowles, J. A.; Guttridge, P.; Gabriel, A. H.; Firth, J. G.; Hayes, R. W.

1980-01-01

The paper considers the soft X-ray polychromator (XRP) operating in the 1.4-22.4 A range of the soft X-ray spectrum which includes many emission lines important for the diagnosis of plasmas in the 1.5-50 million deg temperature range. The flat crystal scanning spectrometer provides for a channel polychromatic mapping of flares and active regions in the resonance lines of O VIII, Ne IX, and Mg XI; in its spectral scanning mode it covers essentially the entire 1.4-22.5 A region.

The soft X-ray polychromator for the Solar Maximum Mission

NASA Astrophysics Data System (ADS)

Acton, L. W.; Culhane, J. L.; Gabriel, A. H.; Bentley, R. D.; Bowles, J. A.; Firth, J. G.; Finch, M. L.; Gilbreth, C. W.; Guttridge, P.; Hayes, R. W.; Joki, E. G.; Jones, B. B.; Kent, B. J.; Leibacher, J. W.; Nobles, R. A.; Patrick, T. J.; Phillips, K. J. H.; Rapley, C. G.; Sheather, P. H.; Sherman, J. C.; Stark, J. P.; Springer, L. A.; Turner, R. F.; Wolfson, C. J.

1980-02-01

The paper considers the soft X-ray polychromator (XRP) operating in the 1.4-22.4 A range of the soft X-ray spectrum which includes many emission lines important for the diagnosis of plasmas in the 1.5-50 million deg temperature range. The flat crystal scanning spectrometer provides for a channel polychromatic mapping of flares and active regions in the resonance lines of O VIII, Ne IX, and Mg XI; in its spectral scanning mode it covers essentially the entire 1.4-22.5 A region.

Technological aspects of GEM detector design and assembling for soft x-ray application

NASA Astrophysics Data System (ADS)

Kowalska-Strzeciwilk, E.; Chernyshova, M.

2016-09-01

Various types of Micro Pattern Gas Detectors (MPGDs) found applications as tracking detectors in high energy particle physics experiments and as well as imaging detectors, especially for soft X-rays. These detectors offer several advantages like high count rate capability, good spatial and energy resolution, low cost and possibility of constructing large area detectors with very small dead area. Construction, like the triple Gas Electron Multiplier (GEM) detector has become a standard detector, which is widely used for different imaging applications. Some examples of such applications are: monitoring the impurity in plasma, imaging system for mapping of some parameters like pigment distributions using X-ray fluorescence technique[1], proton range radiography system for quality assurance in hadron therapy. Measuring of the Soft X-Ray (SXR) radiation of magnetic fusion plasma is a standard way of accessing valuable information, for example, about particle transport and MHD. The paper is focused on the design of GEM based soft Xray radiation detecting system which is under development. It is dedicated to study soft X-ray emission of plasma radiation with focus on tungsten emission lines energy region. The paper presents the designing, construction and assembling of a prototype of two triple-GEM detectors for soft-X ray application on the WEST device.

Lasers, extreme UV and soft X-ray

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nilsen, Joseph

2015-09-20

Three decades ago, large ICF lasers that occupied entire buildings were used as the energy sources to drive the first X-ray lasers. Today X-ray lasers are tabletop, spatially coherent, high-repetition rate lasers that enable many of the standard optical techniques such as interferometry to be extended to the soft X-ray regime between wavelengths of 10 and 50 nm. Over the last decade X-ray laser performance has been improved by the use of the grazing incidence geometry, diode-pumped solid-state lasers, and seeding techniques. The dominant X-ray laser schemes are the monopole collisional excitation lasers either driven by chirped pulse amplification (CPA)more » laser systems or capillary discharge. The CPA systems drive lasing in neon-like or nickel-like ions, typically in the 10 – 30 nm range, while the capillary system works best for neon-like argon at 46.9 nm. Most researchers use nickel-like ion lasers near 14 nm because they are well matched to the Mo:Si multilayer mirrors that have peak reflectivity near 13 nm and are used in many applications. As a result, the last decade has seen the birth of the X-ray free electron laser (XFEL) that can reach wavelengths down to 0.15 nm and the inner-shell Ne laser at 1.46 nm.« less

Fast soft x-ray images of magnetohydrodynamic phenomena in NSTX.

PubMed

Bush, C E; Stratton, B C; Robinson, J; Zakharov, L E; Fredrickson, E D; Stutman, D; Tritz, K

2008-10-01

A variety of magnetohydrodynamic (MHD) phenomena have been observed on NSTX. Many of these affect fast particle losses, which are of major concern for future burning plasma experiments. Usual diagnostics for studying these phenomena are arrays of Mirnov coils for magnetic oscillations and p-i-n diode arrays for soft x-ray emission from the plasma core. Data reported here are from a unique fast soft x-ray imaging camera (FSXIC) with a wide-angle (pinhole) tangential view of the entire plasma minor cross section. The camera provides a 64x64 pixel image, on a charge coupled device chip, of light resulting from conversion of soft x rays incident on a phosphor to the visible. We have acquired plasma images at frame rates of 1-500 kHz (300 frames/shot) and have observed a variety of MHD phenomena: disruptions, sawteeth, fishbones, tearing modes, and edge localized modes (ELMs). New data including modes with frequency >90 kHz are also presented. Data analysis and modeling techniques used to interpret the FSXIC data are described and compared, and FSXIC results are compared to Mirnov and p-i-n diode array results.

Hot and dense plasma probing by soft X-ray lasers

NASA Astrophysics Data System (ADS)

Krůs, M.; Kozlová, M.; Nejdl, J.; Rus, B.

2018-01-01

Soft X-ray lasers, due to their short wavelength, its brightness, and good spatial coherence, are excellent sources for the diagnostics of dense plasmas (up to 1025 cm-3) which are relevant to e.g. inertial fusion. Several techniques and experimental results, which are obtained at the quasi-steady state scheme being collisionally pumped 21.2 nm neon-like zinc laser installed at PALS Research Center, are presented here; among them the plasma density measurement by a double Lloyd mirror interferometer, deflectometer based on Talbot effect measuring plasma density gradients itself, with a following ray tracing postprocessing. Moreover, the high spatial resolution (nm scale) plasma images can be obtained when soft X-ray lasers are used.

Soft x-ray absorption spectra of ilmenite family.

PubMed

Agui, A; Mizumaki, M; Saitoh, Y; Matsushita, T; Nakatani, T; Fukaya, A; Torikai, E

2001-03-01

We have carried out soft x-ray absorption spectroscopy to study the electronic structure of ilmenite family, such as MnTiO3, FeTiO3, and CoTiO3 at the soft x-ray beamline, BL23SU, at the SPring-8. The Ti and M L2,3 absorption spectra of MTiO3 (M=Mn, Fe, and Co) show spectra of Ti4+ and M2+ electron configurations, respectively. Except the Fe L2,3 spectrum, those spectra were understood within the O(h) symmetry around the transition metal ions. The Fe L3-edge spectrum clearly shows a doublet peak at the L3 edge, which is attributed to Fe2+ state, moreover the very high-resolution the L-edge spectra of transition metals show fine structures. The spectra of those ilmenites are compared.

The soft x-ray beamline at Frascati Labs

NASA Astrophysics Data System (ADS)

Cinque, Gianfelice; Burattini, Emilio; Grilli, Antonio; Dabagov, Sultan

2005-08-01

DAΦNE-Light is the Synchrotron Radiation laboratory at the Laboratori Nazionali di Frascati (LNF)1. Three beamlines were commissioned since spring 2003 to exploit parasitically the intense photon emission from DAΦNE, the 0.5 1 GeV storage ring routinely circulating over 1 A of electrons. The soft X-ray beamline utilizes a wiggler source and, by a double-crystal fixed-exit monochromator, it is operational in the distinguishing energy window 1.5 - 4 keV range to be extended from the "water window" toward 6 keV. At present, the research activity is focused on X-ray Absorption Spectroscopy (XAS): precisely, X-ray Absorption Near Edge Spectroscopy (XANES) on the inner electronic levels of light elements and transition metals from Al to Ge and both d- and f-shells of higher Z atoms. Preliminary tests of X-ray imaging have been performed in view of applying different focusing optics, namely policapillary systems in trasmission and/or bent mica diffractor in back-reflection, for X-ray microscopy and spectromicroscopy experiments. The use of polycapillary systems (lenses, halflenses, capillaries) for studying features of radiation transportation by such structures (X-ray channelling, focusing, bending, etc.) has been planned.

Detection of Heating Processes in Coronal Loops by Soft X-ray Spectroscopy

NASA Astrophysics Data System (ADS)

Kawate, Tomoko; Narukage, Noriyuki; Ishikawa, Shin-nosuke; Imada, Shinsuke

2017-08-01

Imaging and Spectroscopic observations in the soft X-ray band will open a new window of the heating/acceleration/transport processes in the solar corona. The soft X-ray spectrum between 0.5 and 10 keV consists of the electron thermal free-free continuum and hot coronal lines such as O VIII, Fe XVII, Mg XI, Si XVII. Intensity of free-free continuum emission is not affected by the population of ions, whereas line intensities especially from highly ionized species have a sensitivity of the timescale of ionization/recombination processes. Thus, spectroscopic observations of both continuum and line intensities have a capability of diagnostics of heating/cooling timescales. We perform a 1D hydrodynamic simulation coupled with the time-dependent ionization, and calculate continuum and line intensities under different heat input conditions in a coronal loop. We also examine the differential emission measure of the coronal loop from the time-integrated soft x-ray spectra. As a result, line intensity shows a departure from the ionization equilibrium and shows different responses depending on the frequency of the heat input. Solar soft X-ray spectroscopic imager will be mounted in the sounding rocket experiment of the Focusing Optics X-ray Solar Imager (FOXSI). This observation will deepen our understanding of heating processes to solve the “coronal heating problem”.

Fingerprints of orbital physics in magnetic resonant inelastic X-ray scattering

NASA Astrophysics Data System (ADS)

Marra, Pasquale

2012-09-01

Orbital degrees of freedom play a major role in the physics of many strongly correlated transition metal compounds. However, they are still very difficult to access experimentally, in particular by neutron scattering. We propose here how to reveal orbital occupancies of the system ground state by magnetic resonant inelastic x-ray scattering (RIXS). This is possible because, unlike in neutron scattering, the intensity of the magnetic excitations in RIXS depends essentially on the symmetry of the orbitals where the spins are in.

Vibrational effects in x-ray absorption and resonant inelastic x-ray scattering using a semiclassical scheme

NASA Astrophysics Data System (ADS)

Ljungberg, Mathias P.

2017-12-01

A method is presented for describing vibrational effects in x-ray absorption spectroscopy and resonant inelastic x-ray scattering (RIXS) using a combination of the classical Franck-Condon (FC) approximation and classical trajectories run on the core-excited state. The formulation of RIXS is an extension of the semiclassical Kramers-Heisenberg formalism of Ljungberg et al. [Phys. Rev. B 82, 245115 (2010), 10.1103/PhysRevB.82.245115] to the resonant case, retaining approximately the same computational cost. To overcome difficulties with connecting the absorption and emission processes in RIXS, the classical FC approximation is used for the absorption, which is seen to work well provided that a zero-point-energy correction is included. In the case of core-excited states with dissociative character, the method is capable of closely reproducing the main features for one-dimensional test systems, compared to the quantum-mechanical formulation. Due to the good accuracy combined with the relatively low computational cost, the method has great potential of being used for complex systems with many degrees of freedom, such as liquids and surface adsorbates.

High spatial resolution soft-x-ray microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meyer-Ilse, W.; Medecki, H.; Brown, J.T.

1997-04-01

A new soft x-ray microscope (XM-1) with high spatial resolution has been constructed by the Center for X-ray Optics. It uses bending magnet radiation from beamline 6.1 at the Advanced Light Source, and is used in a variety of projects and applications in the life and physical sciences. Most of these projects are ongoing. The instrument uses zone plate lenses and achieves a resolution of 43 nm, measured over 10% to 90% intensity with a knife edge test sample. X-ray microscopy permits the imaging of relatively thick samples, up to 10 {mu}m thick, in water. XM-1 has an easy tomore » use interface, that utilizes visible light microscopy to precisely position and focus the specimen. The authors describe applications of this device in the biological sciences, as well as in studying industrial applications including structured polymer samples.« less

Energetics and timing of the hard and soft X-ray emissions in white light flares

NASA Technical Reports Server (NTRS)

Neidig, Donald F.; Kane, Sharad R.

1993-01-01

By comparing the light curves in optical, hard X-ray, and soft X-ray wavelengths for eight well-observed flares, we confirm previous results indicating that the white light flare (WLF) is associated with the flare impulsive phase. The WLF emission peaks within seconds after the associated hard X-ray peak, and nearly two minutes before the 1-8 A soft X-ray peak. It is further shown that the peak power in nonthermal electrons above 50 keV is typically an order of magnitude larger, and the power in 1-8 A soft X-rays radiated over 2pi sr, at the time of the WLF peak, is an order of magnitude smaller than the peak WLF power.

MESSENGER soft X-ray observations of the quiet solar corona

NASA Astrophysics Data System (ADS)

Schwartz, Richard A.; Hudson, Hugh S.; Tolbert, Anne K; Dennis, Brian R.

2014-06-01

In a remarkable result from their "SphinX" experiment, Sylwester et al. (2012) found a non-varying base level of soft X-ray emission at the quietest times in 2009. We describe comparable data from the soft X-ray monitor on board MESSENGER (en route to Mercury) which had excellent coverage both in 2009 and during the true solar minimum of 2008. These observations overlap SphinX's and also are often exactly at Sun-MESSENGER-Earth conjunctions. During solar minimum the Sun-MESSENGER distance varied substantially, allowing us to use the inverse-square law to help distinguish the aperture flux (ie, solar X-rays) from that due to sources of background in the 2-5 keV range. The MESSENGER data show a non-varying background level for many months in 2008 when no active regions were present. We compare these data in detail with those from SphinX. Both sets of data reveal a different behavior when magnetic active regions are present on the Sun, and when they are not.Reference: Sylwester et al., ApJ 751, 111 (2012)

Dante soft x-ray power diagnostic for National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dewald, E.L.; Campbell, K.M.; Turner, R.E.

2004-10-01

Soft x-ray power diagnostics are essential for measuring the total x-ray flux, radiation temperature, conversion efficiency, and albedo that define the energetics in indirect and direct drive, as well as other types of high temperature laser plasma experiments. A key diagnostic for absolute radiation flux and radiation temperature in hohlraum experiments is the Dante broadband soft x-ray spectrometer. For the extended range of x-ray fluxes predicted for National Ignition Facility (NIF) compared to Omega or Nova hohlraums, the Dante spectrometer for NIF will include more high energy (<2 keV) edge filter band-pass channels and access to an increased dynamic rangemore » using grids and signal division. This will allow measurements of radiation fluxes of between 0.01 to 100 TW/sr, for hohlraum radiation temperatures between 50 eV and 1 keV. The NIF Dante will include a central four-channel imaging line-of-sight to verify the source size, alignment as well as checking for any radiation contributions from unconverted laser light plasmas.« less

Soft x-ray holographic tomography for biological specimens

NASA Astrophysics Data System (ADS)

Gao, Hongyi; Chen, Jianwen; Xie, Honglan; Li, Ruxin; Xu, Zhizhan; Jiang, Shiping; Zhang, Yuxuan

2003-10-01

In this paper, we present some experimental results on X -ray holography, holographic tomography, and a new holographic tomography method called pre-amplified holographic tomography is proposed. Due to the shorter wavelength and the larger penetration depths, X-rays provide the potential of higher resolution in imaging techniques, and have the ability to image intact, living, hydrated cells w ithout slicing, dehydration, chemical fixation or stain. Recently, using X-ray source in National Synchrotron Radiation Laboratory in Hefei, we have successfully performed some soft X-ray holography experiments on biological specimen. The specimens used in the experiments was the garlic clove epidermis, we got their X-ray hologram, and then reconstructed them by computer programs, the feature of the cell walls, the nuclei and some cytoplasm were clearly resolved. However, there still exist some problems in realization of practical 3D microscopic imaging due to the near-unity refractive index of the matter. There is no X-ray optics having a sufficient high numerical aperture to achieve a depth resolution that is comparable to the transverse resolution. On the other hand, computer tomography needs a record of hundreds of views of the test object at different angles for high resolution. This is because the number of views required for a densely packed object is equal to the object radius divided by the desired depth resolution. Clearly, it is impractical for a radiation-sensitive biological specimen. Moreover, the X-ray diffraction effect makes projection data blur, this badly degrades the resolution of the reconstructed image. In order to observe 3D structure of the biological specimens, McNulty proposed a new method for 3D imaging called "holographic tomography (HT)" in which several holograms of the specimen are recorded from various illumination directions and combined in the reconstruction step. This permits the specimens to be sampled over a wide range of spatial

The soft x ray telescope for Solar-A

NASA Technical Reports Server (NTRS)

Brown, W. A.; Acton, L. W.; Bruner, M. E.; Lemen, J. R.; Strong, K. T.

1989-01-01

The Solar-A satellite being prepared by the Institute for Sapce and Astronautical Sciences (ISAS) in Japan is dedicated to high energy observations of solar flares. The Soft X Ray Telescope (SXT) is being prepared to provide filtered images in the 2 to 60 A interval. The flight model is now undergoing tests in the 1000 foot tunnel at MSFC. Launch will be in September 1991. Earlier resolution and efficiency tests on the grazing incidence mirror have established its performance in soft x rays. The one-piece, two mirror grazing incidence telescope is supported in a strain free mount separated from the focal plane assembly by a carbon-epoxy metering tube whose windings and filler are chosen to minimize thermal and hygroscopic effects. The CCD detector images both the x ray and the concentric visible light aspect telescope. Optical filters provide images at 4308 and 4700 A. The SXT will be capable of producing over 8000 of the smallest partial frame images per day, or fewer but larger images, up to 1024 x 1024 pixel images. Image sequence with two or more of the five x ray analysis filters, with automatic exposure compensation to optimize the charge collection by the CCD detector, will be used to provide plasma diagnostics. Calculations using a differential emission measure code were used to optimize filter selection over the range of emission measure variations and to avoid redundancy, but the filters were chosen primarily to give ratios that are monotonic in plasma temperature.

A search for soft X-ray emission from red-giant coronae

NASA Technical Reports Server (NTRS)

Margon, B.; Mason, K. O.; Sanford, P. W.

1974-01-01

Hills has pointed out that if red-giant coronae are weak sources of soft X-rays, then the problems of the identification of the local component of the soft X-ray background and the observed lack of gas in globular clusters may be simultaneously resolved. Using instrumentation aboard OAO Copernicus, we have searched unsuccessfully for emission in the 10-100 A band from four nearby red giants. In all cases, our upper limits are of the order of the minimum theoretically predicted fluxes.

The correlation of solar flare hard X-ray bursts with Doppler blueshifted soft X-ray flare emission

NASA Technical Reports Server (NTRS)

Bentley, R. D.; Doschek, G. A.; Simnett, G. M.; Rilee, M. L.; Mariska, J. T.; Culhane, J. L.; Kosugi, T.; Watanabe, T.

1994-01-01

We have investigated the temporal correlation between hard X-ray bursts and the intensity of Doppler blueshifted soft X-ray spectral line emission. We find a strong correlation for many events that have intense blueshifted spectral signatures and some correlation in events with modest blueshifts. The onset of hard X-rays frequently coincides to within a few seconds with the onset of blueshifted emission. The peak intensity of blueshifted emission is frequently close in time to the peak of the hard X-ray emission. Decay rates of the blueshifted and hard X-ray emission are similar, with the decay of the blueshifted emission tending to lag behind the hard X-ray emission in some cases. There are, however, exceptions to these conclusions, and, therefore, the results should not be generalized to all flares. Most of the data for this work were obtained from instruments flown on the Japanese Yohkoh solar spacecraft.

Two new intermediate polars with a soft X-ray component

NASA Astrophysics Data System (ADS)

Anzolin, G.; de Martino, D.; Bonnet-Bidaud, J.-M.; Mouchet, M.; Gänsicke, B. T.; Matt, G.; Mukai, K.

2008-10-01

Aims: We analyze the first X-ray observations with XMM-Newton of 1RXS J070407.9+262501 and 1RXS 180340.0+401214, in order to characterize their broad-band temporal and spectral properties, also in the UV/optical domain, and to confirm them as intermediate polars. Methods: For both objects, we performed a timing analysis of the X-ray and UV/optical light curves to detect the white dwarf spin pulsations and study their energy dependence. For 1RXS 180340.0+401214 we also analyzed optical spectroscopic data to determine the orbital period. X-ray spectra were analyzed in the 0.2-10.0 keV range to characterize the emission properties of both sources. Results: We find that the X-ray light curves of both systems are energy dependent and are dominated, below 3-5 keV, by strong pulsations at the white dwarf rotational periods (480 s for 1RXS J070407.9+262501 and 1520.5 s for 1RXS 180340.0+401214). In 1RXS 180340.0+401214 we also detect an X-ray beat variability at 1697 s which, together with our new optical spectroscopy, favours an orbital period of 4.4 h that is longer than previously estimated. Both systems show complex spectra with a hard (temperature up to 40 keV) optically thin and a soft (kT ~ 85-100 eV) optically thick components heavily absorbed by material partially covering the X-ray sources. Conclusions: Our observations confirm the two systems as intermediate polars and also add them as new members of the growing group of “soft” systems which show the presence of a soft X-ray blackbody component. Differences in the temperatures of the blackbodies are qualitatively explained in terms of reprocessing over different sizes of the white dwarf spot. We suggest that systems showing cooler soft X-ray blackbody components also possess white dwarfs irradiated by cyclotron radiation. Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA, and with the Observatoire de Haute

Soft x-ray coherent diffraction imaging on magnetic nanostructures

NASA Astrophysics Data System (ADS)

Shi, Xiaowen; Lee, James; Mishra, Shrawan; Parks, Daniel; Tyliszczak, Tolek; Shapiro, David; Roy, Sujoy; Kevan, Steve; Stxm Team At Als Collaboration; Soft X-Ray Microscopy Group At Als Collaboration; Soft X-ray scattering at ALS, LBL Team

2014-03-01

Coherent soft X-rays diffraction imaging enable coherent magnetic resonance scattering at transition metal L-edge to be probed so that magnetic domains could be imaged with very high spatial resolution with phase contrast, reaching sub-10nm. One of the overwhelming advantages of using coherent X-rays is the ability to resolve phase contrast images with linearly polarized light with both phase and absorption contrast comparing to real-space imaging, which can only be studied with circularly polarized light with absorption contrast only. Here we report our first results on high-resolution of magnetic domains imaging of CoPd multilayer thin film with coherent soft X-ray ptychography method. We are aiming to resolve and understand magnetic domain wall structures with the highest obtainable resolution here at Advanced Light Source. In principle types of magnetic domain walls could be studied so that Neel or Bloch walls can be distinguished by imaging. This work at LBNL was supported by the Director, Office of Science, Office of Basic Energy Sciences, of the US Department of Energy (contract no. DE-AC02- 05CH11231).

A model for soft X-ray transients

NASA Astrophysics Data System (ADS)

Hameury, J. M.; King, A. R.; Lasota, J. P.

1986-07-01

The existing database on the physical characteristics of stellar soft and ultrasoft transient X-ray bursts is summarized in order to form a generic model for the sources. The bursts have come from binary systems which repeat the bursts with a frequency of about a year. Bursts possess energies of about 10 to the 44th ergs emitted for months and reaching maximum luminosities of 10 to the 37th to 10 to the 38th ergs, levels associated with an accretion rate of 10 billion grams/sec. The transients are shown to arise because of a mass loss instability in the secondary star, believed to be red dwarf. Analysis of the structure of the envelope of a dwarf heated by X-rays shows that subphotospheric layers can expand during the quiescent phase and enter into a mass transfer instability condition near the Roche lobe. The accretion disk eventually blocks the X-ray input and the transfer to the primary, a neutron star, abates.

Soft X-ray observations of two BL Lacertae objects - Markarian 421 and 501

NASA Technical Reports Server (NTRS)

Singh, K. P.; Garmire, G. P.

1985-01-01

This paper reports on the soft X-ray (0.15-2.8 keV) observations of two BL Lacertae-type objects, viz., Mrk 421 and Mrk 501. The observations were made with the low-energy detectors on the HEAO 1 satellite during the period 1977 August-1978 December. Steep, soft X-ray power-law spectra with photon index Gamma = 3 are found for both Mrk 421 and Mrk 501. The power-law models are found to give a significantly better fit than the thermal models to the observed pulse-height spectra of Mrk 421 and Mrk 501. Day-to-day soft X-ray (0.25 keV band) intensity variations are observed only in Mrk 501. No significant change is found in Gamma from both the BL Lac objects during the period of observations. However, the sum of all the X-ray observations from 1976 until 1980 can be understood in terms of two spectral components of variable intensity to account for the X-ray emission observed between 0.15 and 20 keV from Mrk 421 and Mrk 501.

Exploring the Hard and Soft X-ray Emission of Magnetic Cataclysmic Variables

NASA Astrophysics Data System (ADS)

de Martino, D.; Anzolin, G.; Bonnet-Bidaud, J.-M.; Falanga, M.; Matt, G.; Mouchet, M.; Mukai, K.; Masetti, N.

2009-05-01

A non-negligible fraction of galactic hard (>20 keV) X-ray sources were identified as CVs of the magnetic Intermediate Polar type in INTEGRAL, SWIFT and RXTE surveys, that suggests a still hidden but potentially important population of faint hard X-ray sources. Simbol-X has the unique potential to simultaneously characterize their variable and complex soft and hard X-ray emission thus allowing to understand their putative role in galactic populations of X-ray sources.

X-ray Echo Spectroscopy

NASA Astrophysics Data System (ADS)

Shvyd'ko, Yuri

2016-02-01

X-ray echo spectroscopy, a counterpart of neutron spin echo, is being introduced here to overcome limitations in spectral resolution and weak signals of the traditional inelastic x-ray scattering (IXS) probes. An image of a pointlike x-ray source is defocused by a dispersing system comprised of asymmetrically cut specially arranged Bragg diffracting crystals. The defocused image is refocused into a point (echo) in a time-reversal dispersing system. If the defocused beam is inelastically scattered from a sample, the echo signal acquires a spatial distribution, which is a map of the inelastic scattering spectrum. The spectral resolution of the echo spectroscopy does not rely on the monochromaticity of the x rays, ensuring strong signals along with a very high spectral resolution. Particular schemes of x-ray echo spectrometers for 0.1-0.02 meV ultrahigh-resolution IXS applications (resolving power >108 ) with broadband ≃5 - 13 meV dispersing systems are introduced featuring more than 103 signal enhancement. The technique is general, applicable in different photon frequency domains.

Millimeter, microwave, hard X-ray, and soft X-ray observations of energetic electron populations in solar flares

NASA Technical Reports Server (NTRS)

Kundu, M. R.; White, S. M.; Gopalswamy, N.; Lim, J.

1994-01-01

We present comparisons of multiwavelength data for a number of solar flares observed during the major campaign of 1991 June. The different wavelengths are diagnostics of energetic electrons in different energy ranges: soft X-rays are produced by electrons with energies typically below 10 keV, hard X-rays by electrons with energies in the range 10-200 keV, microwaves by electrons in the range 100 keV-1 MeV, and millimeter-wavelength emission by electrons with energies of 0.5 MeV and above. The flares in the 1991 June active period were remarkable in two ways: all have very high turnover frequencies in their microwave spectra, and very soft hard X-ray spectra. The sensitivity of the microwave and millimeter data permit us to study the more energetic (greater than 0.3 MeV) electrons even in small flares, where their high-energy bremsstrahlung is too weak for present detectors. The millimeter data show delays in the onset of emission with respect to the emissions associated with lower energy electrons and differences in time profiles, energy spectral indices incompatible with those implied by the hard X-ray data, and a range of variability of the peak flux in the impulsive phase when compared with the peak hard X-ray flux which is two orders of magnitude larger than the corresponding variability in the peak microwave flux. All these results suggest that the hard X-ray-emitting electrons and those at higher energies which produce millimeter emission must be regarded as separate populations. This has implications for the well-known 'number problem' found previously when comparing the numbers of non thermal electrons required to produce the hard X-ray and radio emissions.

Dzyaloshinskii-Moriya interaction in α -Fe2O3 measured by magnetic circular dichroism in resonant inelastic soft x-ray scattering

NASA Astrophysics Data System (ADS)

Miyawaki, Jun; Suga, Shigemasa; Fujiwara, Hidenori; Urasaki, Masato; Ikeno, Hidekazu; Niwa, Hideharu; Kiuchi, Hisao; Harada, Yoshihisa

2017-12-01

Fe L2 ,3-edge x-ray absorption spectra (XAS) and magnetic circular dichroism (MCD) in resonant inelastic x-ray scattering (RIXS) of α -Fe2O3 were measured to identify the electronic structure responsible for its weak ferromagnetism caused by the Dzyaloshinskii-Moriya interaction (DMI) at room temperature. In contrast to negligible MCD in XAS, MCD in RIXS (RIXS-MCD) was clearly observed in the d d excitation at 1.8 eV via excitation to charge-transfer states. Furthermore, RIXS-MCD showed a crystal orientation dependence, indicating that the observed RIXS-MCD originated from DMI. The observed RIXS-MCD is well described by ab initio charge-transfer multiplet calculations, revealing that the RIXS-MCD derives from spin flip excitations at delocalized eg orbitals. By the combination of the experiments and calculations, RIXS-MCD has unraveled that the origin of DMI in α -Fe2O3 is the eg orbitals, which are strongly hybridized with the 2 p orbitals of oxygen atoms. The results demonstrate the importance of RIXS-MCD for identifying the electronic structure related to DMI.

Ultra-high-resolution inelastic X-ray scattering at high-repetition-rate self-seeded X-ray free-electron lasers

PubMed Central

Chubar, Oleg; Geloni, Gianluca; Kocharyan, Vitali; Madsen, Anders; Saldin, Evgeni; Serkez, Svitozar; Shvyd’ko, Yuri; Sutter, John

2016-01-01

Inelastic X-ray scattering (IXS) is an important tool for studies of equilibrium dynamics in condensed matter. A new spectrometer recently proposed for ultra-high-resolution IXS (UHRIX) has achieved 0.6 meV and 0.25 nm−1 spectral and momentum-transfer resolutions, respectively. However, further improvements down to 0.1 meV and 0.02 nm−1 are required to close the gap in energy–momentum space between high- and low-frequency probes. It is shown that this goal can be achieved by further optimizing the X-ray optics and by increasing the spectral flux of the incident X-ray pulses. UHRIX performs best at energies from 5 to 10 keV, where a combination of self-seeding and undulator tapering at the SASE-2 beamline of the European XFEL promises up to a 100-fold increase in average spectral flux compared with nominal SASE pulses at saturation, or three orders of magnitude more than what is possible with storage-ring-based radiation sources. Wave-optics calculations show that about 7 × 1012 photons s−1 in a 90 µeV bandwidth can be achieved on the sample. This will provide unique new possibilities for dynamics studies by IXS. PMID:26917127

Ultra-high-resolution inelastic X-ray scattering at high-repetition-rate self-seeded X-ray free-electron lasers

DOE PAGES

Chubar, Oleg; Geloni, Gianluca; Kocharyan, Vitali; ...

2016-03-01

Inelastic X-ray scattering (IXS) is an important tool for studies of equilibrium dynamics in condensed matter. A new spectrometer recently proposed for ultra-high-resolution IXS (UHRIX) has achieved 0.6 meV and 0.25 nm ₋1spectral and momentum-transfer resolutions, respectively. However, further improvements down to 0.1 meV and 0.02 nm ₋1are required to close the gap in energy–momentum space between high- and low-frequency probes. It is shown that this goal can be achieved by further optimizing the X-ray optics and by increasing the spectral flux of the incident X-ray pulses. UHRIX performs best at energies from 5 to 10 keV, where a combinationmore » of self-seeding and undulator tapering at the SASE-2 beamline of the European XFEL promises up to a 100-fold increase in average spectral flux compared with nominal SASE pulses at saturation, or three orders of magnitude more than what is possible with storage-ring-based radiation sources. Wave-optics calculations show that about 7 × 10 12 photons s ₋1in a 90 µeV bandwidth can be achieved on the sample. Ultimately, this will provide unique new possibilities for dynamics studies by IXS.« less

The diversity of soft X-ray spectra in quasars

NASA Technical Reports Server (NTRS)

Elvis, M.; Wilkes, B. J.; Tananbaum, H.

1985-01-01

Soft X-ray spectra for three quasars obtained with the Einstein Imaging Proportional Counter covering the 0.1-4.0 keV band are reported. Power-law fits to these spectra have best-fit energy indices of 1.2 +0.6 or -0.2, for the quasar NAB 0205 + 024, 0.6 +0.3 or -0.2 for the quasar B2 1028 + 313, and 2.2 + or -0.4 for the quasar PG 1211 + 143. None of the quasars shows any evidence for a column density of cold matter in excess of the galactic values. The derived spectra demonstrate that there is no single universal power law slope for quasar X-ray spectra. The implications of these results for the X-ray background, X-ray continuum emission mechanisms, and the production of the optical/UV emission lines are briefly discussed.

Surface layering and melting in an ionic liquid studied by resonant soft X-ray reflectivity

PubMed Central

Mezger, Markus; Ocko, Benjamin M.; Reichert, Harald; Deutsch, Moshe

2013-01-01

The molecular-scale structure of the ionic liquid [C18mim]+[FAP]− near its free surface was studied by complementary methods. X-ray absorption spectroscopy and resonant soft X-ray reflectivity revealed a depth-decaying near-surface layering. Element-specific interfacial profiles were extracted with submolecular resolution from energy-dependent soft X-ray reflectivity data. Temperature-dependent hard X-ray reflectivity, small- and wide-angle X-ray scattering, and infrared spectroscopy uncovered an intriguing melting mechanism for the layered region, where alkyl chain melting drove a negative thermal expansion of the surface layer spacing. PMID:23431181

Soft X-Ray Observations of a Complete Sample of X-Ray--selected BL Lacertae Objects

NASA Astrophysics Data System (ADS)

Perlman, Eric S.; Stocke, John T.; Wang, Q. Daniel; Morris, Simon L.

1996-01-01

We present the results of ROSAT PSPC observations of the X-ray selected BL Lacertae objects (XBLs) in the complete Einstein Extended Medium Sensitivity Survey (EM MS) sample. None of the objects is resolved in their respective PSPC images, but all are easily detected. All BL Lac objects in this sample are well-fitted by single power laws. Their X-ray spectra exhibit a variety of spectral slopes, with best-fit energy power-law spectral indices between α = 0.5-2.3. The PSPC spectra of this sample are slightly steeper than those typical of flat ratio-spectrum quasars. Because almost all of the individual PSPC spectral indices are equal to or slightly steeper than the overall optical to X-ray spectral indices for these same objects, we infer that BL Lac soft X-ray continua are dominated by steep-spectrum synchrotron radiation from a broad X-ray jet, rather than flat-spectrum inverse Compton radiation linked to the narrower radio/millimeter jet. The softness of the X-ray spectra of these XBLs revives the possibility proposed by Guilbert, Fabian, & McCray (1983) that BL Lac objects are lineless because the circumnuclear gas cannot be heated sufficiently to permit two stable gas phases, the cooler of which would comprise the broad emission-line clouds. Because unified schemes predict that hard self-Compton radiation is beamed only into a small solid angle in BL Lac objects, the steep-spectrum synchrotron tail controls the temperature of the circumnuclear gas at r ≤ 1018 cm and prevents broad-line cloud formation. We use these new ROSAT data to recalculate the X-ray luminosity function and cosmological evolution of the complete EMSS sample by determining accurate K-corrections for the sample and estimating the effects of variability and the possibility of incompleteness in the sample. Our analysis confirms that XBLs are evolving "negatively," opposite in sense to quasars, with Ve/Va = 0.331±0.060. The statistically significant difference between the values for

Development of optical choppers for time-resolved measurements at soft X-ray synchrotron radiation beamlines

PubMed Central

Osawa, Hitoshi; Ohkochi, Takuo; Fujisawa, Masami; Kimura, Shigeru; Kinoshita, Toyohiko

2017-01-01

Two types of optical choppers for time-resolved measurements at synchrotron radiation soft X-ray beamlines have been developed. One type uses an air-spindle-type rotation mechanism with a two-stage differential pumping system to maintain the ultra-high vacuum of the X-ray beamline, and the other uses a magnetic bearing. Both can be installed at the soft X-ray beamlines at SPring-8, greatly improving the accessibility of pump-and-probe spectroscopy. The combination of X-ray chopper and pump-and-probe photoemission electron microscope at SPring-8 provides drastic improvements in signal-to-noise ratio and resolution compared with techniques using high-voltage gating of channel plate detectors. The choppers have the capability to be used not only at synchrotron radiation facilities but also at other types of soft X-ray and VUV beamlines. PMID:28452746

Soft X-ray study of solar wind charge exchange from the Earth's magnetosphere : Suzaku observations and a future X-ray imaging mission concept

NASA Astrophysics Data System (ADS)

Ezoe, Y.; Ishisaki, Y.; Ohashi, T.; Ishikawa, K.; Miyoshi, Y.; Fujimoto, R.; Terada, N.; Kasahara, S.; Fujimoto, M.; Mitsuda, K.; Nishijo, K.; Noda, A.

2013-12-01

Soft X-ray observations of solar wind charge exchange (SWCX) emission from the Earth's magnetosphere using the Japanese X-ray astronomy satellite Suzaku are shown, together with our X-ray imaging mission concept to characterize the solar wind interaction with the magnetosphere. In recent years, the SWCX emission from the Earth's magnetosphere, originally discovered as unexplained noise during the soft X-ray all sky survey (Snowden et al. 1994), is receiving increased attention on studying geospace. The SWCX is a reaction between neutrals in exosphere and highly charged ions in the magnetosphere originated from solar wind. Robertson et al. (2005) modeled the SWCX emission as seen from an observation point 50 Re from Earth. In the resulting X-ray intensities, the magnetopause, bow shock and cusp were clearly visible. High sensitivity soft X-ray observation with CCDs onboard recent X-ray astronomy satellites enables us to resolve SWCX emission lines and investigate time correlation with solar wind as observed with ACE and WIND more accurately. Suzaku is the 5th Japanese X-ray astronomy satellite launched in 2005. The line of sight direction through cusp is observable, while constraints on Earth limb avoidance angle of other satellites often limits observable regions. Suzaku firstly detected the SWCX emission while pointing in the direction of the north ecliptic pole (Fujimoto et al. 2007). Using the Tsyganenko 1996 magnetic field model, the distance to the nearest SWCX region was estimated as 2-8 Re, implying that the line of sight direction can be through magnetospheric cusp. Ezoe et al. (2010) reported SWCX events toward the sub-solar side of the magnetosheath. These cusp and sub-solar side magnetosheath regions are predicted to show high SWCX fluxes by Robertson et al. (2005). On the other hand, Ishikawa et al. (2013) discovered a similarly strong SWCX event when the line of sight direction did not transverse these two regions. Motivated by these detections

Acoustic phonons in chrysotile asbestos probed by high-resolution inelastic x-ray scattering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mamontov, Eugene; Vakhrushev, S. B.; Kumzerov, Yu. A,

Acoustic phonons in an individual, oriented fiber of chrysotile asbestos (chemical formula Mg{sub 3}Si{sub 2}O{sub 5}(OH){sub 4}) were observed at room temperature in the inelastic x-ray measurement with a very high (meV) resolution. The x-ray scattering vector was aligned along [1 0 0] direction of the reciprocal lattice, nearly parallel to the long axis of the fiber. The latter coincides with [1 0 0] direction of the direct lattice and the axes of the nano-channels. The data were analyzed using a damped harmonic oscillator model. Analysis of the phonon dispersion in the first Brillouin zone yielded the longitudinal sound velocitymore » of (9200 {+-} 600) m/s.« less

Short-duration solar microwave bursts and associated soft X-ray emission. M.S. Thesis

NASA Technical Reports Server (NTRS)

Spangler, S. R.

1972-01-01

Two hundred and fifty-nine short-duration microwave (15.4 GHz) bursts which occurred during the period of January 1968 to March 1970 were correlated with possible soft X-ray (2-12 A) flares occurring simultaneously. Sixty-six percent of the microwave bursts which were observed during periods of soft X-ray data coverage had associated soft X-ray flares. A study of an index of impulsiveness of the microwave flares failed to show a separation of the events into subclasses which could be attributed to distinctly different physical mechanisms. A weak (0.43) correlation was found between the intensities of the microwave and X-ray flares. A very weak (0.15) and statistically questionable correlation was found between the total energy released in these two energy ranges. Two models for the electron acceleration mechanism are discussed.

Soft X-ray production by photon scattering in pulsating binary neutron star sources

NASA Technical Reports Server (NTRS)

Bussard, R. W.; Meszaros, P.; Alexander, S.

1985-01-01

A new mechanism is proposed as a source of soft (less than 1 keV) radiation in binary pulsating X-ray sources, in the form of photon scattering which leaves the electron in an excited Landau level. In a plasma with parameters typical of such sources, the low-energy X-ray emissivity of this mechanism far exceeds that of bremsstrahlung. This copious source of soft photons is quite adequate to provide the seed photons needed to explain the power-law hard X-ray spectrum by inverse Comptonization on the hot electrons at the base of the accretion column.

Anti-contamination device for cryogenic soft X-ray diffraction microscopy

DOE PAGES

Huang, Xiaojing; Miao, Huijie; Nelson, Johanna; ...

2011-05-01

Cryogenic microscopy allows one to view frozen hydrated biological and soft matter specimens with good structural preservation and a high degree of stability against radiation damage. We describe a liquid nitrogen-cooled anti-contamination device for cryogenic X-ray diffraction microscopy. The anti-contaminator greatly reduces the buildup of ice layers on the specimen due to condensation of residual water vapor in the experimental vacuum chamber. We show by coherent X-ray diffraction measurements that this leads to fivefold reduction of background scattering, which is important for far-field X-ray diffraction microscopy of biological specimens.

Prototype high resolution multienergy soft x-ray array for NSTX.

PubMed

Tritz, K; Stutman, D; Delgado-Aparicio, L; Finkenthal, M; Kaita, R; Roquemore, L

2010-10-01

A novel diagnostic design seeks to enhance the capability of multienergy soft x-ray (SXR) detection by using an image intensifier to amplify the signals from a larger set of filtered x-ray profiles. The increased number of profiles and simplified detection system provides a compact diagnostic device for measuring T(e) in addition to contributions from density and impurities. A single-energy prototype system has been implemented on NSTX, comprised of a filtered x-ray pinhole camera, which converts the x-rays to visible light using a CsI:Tl phosphor. SXR profiles have been measured in high performance plasmas at frame rates of up to 10 kHz, and comparisons to the toroidally displaced tangential multi-energy SXR have been made.

How to Model Super-Soft X-ray Sources?

NASA Astrophysics Data System (ADS)

Rauch, Thomas

2012-07-01

During outbursts, the surface temperatures of white dwarfs in cataclysmic variables exceed by far half a million Kelvin. In this phase, they may become the brightest super-soft sources (SSS) in the sky. Time-series of high-resolution, high S/N X-ray spectra taken during rise, maximum, and decline of their X-ray luminosity provide insights into the processes following such outbursts as well as in the surface composition of the white dwarf. Their analysis requires adequate NLTE model atmospheres. The Tuebingen Non-LTE Model-Atmosphere Package (TMAP) is a powerful tool for their calculation. We present the application of TMAP models to SSS spectra and discuss their validity.

Ground-based x-ray calibration of the Astro-H/Hitomi soft x-ray telescopes

NASA Astrophysics Data System (ADS)

Iizuka, Ryo; Hayashi, Takayuki; Maeda, Yoshitomo; Ishida, Manabu; Tomikawa, Kazuki; Sato, Toshiki; Kikuchi, Naomichi; Okajima, Takashi; Soong, Yang; Serlemitsos, Peter J.; Mori, Hideyuki; Izumiya, Takanori; Minami, Sari

2018-01-01

We present the summary of the on-ground calibration of two soft x-ray telescopes (SXT-I and SXT-S), developed by NASA's Goddard Space Flight Center (GSFC), onboard Astro-H/Hitomi. After the initial x-ray measurements with a diverging beam at the GSFC 100-m beamline, we performed the full calibration of the x-ray performance, using the 30-m x-ray beamline facility at the Institute of Space and Astronautical Science of Japan Aerospace Exploration Agency in Japan. We adopted a raster scan method with a narrow x-ray pencil beam with a divergence of ˜15″. The on-axis effective area (EA), half-power diameter, and vignetting function were measured at several energies between 1.5 and 17.5 keV. The detailed results appear in tables and figures in this paper. We measured and evaluated the performance of the SXT-S and the SXT-I with regard to the detector-limited field-of-view and the pixel size of the paired flight detector, i.e., SXS and the SXI, respectively. The primary items measured are the EA, image quality, and stray light for on-axis and off-axis sources. The accurate measurement of these parameters is vital to make the precise response function of the ASTRO-H SXTs. This paper presents the definitive results of the ground-based calibration of the ASTRO-H SXTs.

The rotation-powered nature of some soft gamma-ray repeaters and anomalous X-ray pulsars

NASA Astrophysics Data System (ADS)

Coelho, Jaziel G.; Cáceres, D. L.; de Lima, R. C. R.; Malheiro, M.; Rueda, J. A.; Ruffini, R.

2017-03-01

Context. Soft gamma-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are slow rotating isolated pulsars whose energy reservoir is still matter of debate. Adopting neutron star (NS) fiducial parameters; mass M = 1.4 M⊙, radius R = 10 km, and moment of inertia, I = 1045 g cm2, the rotational energy loss, Ėrot, is lower than the observed luminosity (dominated by the X-rays) LX for many of the sources. Aims: We investigate the possibility that some members of this family could be canonical rotation-powered pulsars using realistic NS structure parameters instead of fiducial values. Methods: We compute the NS mass, radius, moment of inertia and angular momentum from numerical integration of the axisymmetric general relativistic equations of equilibrium. We then compute the entire range of allowed values of the rotational energy loss, Ėrot, for the observed values of rotation period P and spin-down rate Ṗ. We also estimate the surface magnetic field using a general relativistic model of a rotating magnetic dipole. Results: We show that realistic NS parameters lowers the estimated value of the magnetic field and radiation efficiency, LX/Ėrot, with respect to estimates based on fiducial NS parameters. We show that nine SGRs/AXPs can be described as canonical pulsars driven by the NS rotational energy, for LX computed in the soft (2-10 keV) X-ray band. We compute the range of NS masses for which LX/Ėrot< 1. We discuss the observed hard X-ray emission in three sources of the group of nine potentially rotation-powered NSs. This additional hard X-ray component dominates over the soft one leading to LX/Ėrot > 1 in two of them. Conclusions: We show that 9 SGRs/AXPs can be rotation-powered NSs if we analyze their X-ray luminosity in the soft 2-10 keV band. Interestingly, four of them show radio emission and six have been associated with supernova remnants (including Swift J1834.9-0846 the first SGR observed with a surrounding wind nebula). These observations give

High-energy-resolution diced spherical quartz analyzers for resonant inelastic X-ray scattering

DOE PAGES

Said, Ayman H.; Gog, Thomas; Wieczorek, Michael; ...

2018-02-15

A novel diced spherical quartz analyzer for use in resonant inelastic X-ray scattering (RIXS) is introduced, achieving an unprecedented energy resolution of 10.53 meV at the IrL 3absorption edge (11.215 keV). In this work the fabrication process and the characterization of the analyzer are presented, and an example of a RIXS spectrum of magnetic excitations in a Sr 3Ir 2O 7sample is shown.

Interrelation of soft and hard X-ray emissions during solar flares. I - Observations

NASA Technical Reports Server (NTRS)

Winglee, R. M.; Kiplinger, A. L.; Zarro, D. M.; Dulk, G. A.; Lemen, J. R.

1991-01-01

The interrelation between the acceleration and heating of electrons and ions during impulsive solar flares is determined on the basis of simulataneous observations of hard and soft X-ray emission from the Solar Maximum Mission at high time resolution (6 s). For all the flares, the hard X-rays are found to have a power-law spectrum which breaks down during the rise phase and beginning of the decay phase. After that, the spectrum changes to either a single power law or a power law that breaks up at high energies. The characteristics of the soft X-ray are found to depend on the flare position. It is suggested that small-scale quasi-static electric fields are important for determining the acceleration of the X-ray-producing electrons and the outflowing chromospheric ions.

Energetics of impulsive solar flares: Correlating BATSE hard x-ray bursts and the solar atmosphere's soft x-ray response

NASA Technical Reports Server (NTRS)

Newton, Elizabeth

1996-01-01

This investigation has involved the correlation of BATSE-observed solar hard X-ray emission with the characteristics of soft X-ray emitting plasma observed by the Yohkoh Bragg Crystal Spectrometers. The goal was to test the hypothesis that localized electron beam heating is the dominant energy transport mechanism in impulsive flares, as formulated in the thick-target electron-heated model of Brown.

Optimizing soft X-ray NEXAFS spectroscopy in the laboratory

NASA Astrophysics Data System (ADS)

Mantouvalou, I.; Jonas, A.; Witte, K.; Jung, R.; Stiel, H.; Kanngießer, B.

2017-05-01

Near edge X-ray absorption fine structure (NEXAFS) spectroscopy in the soft X-ray range is feasible in the laboratory using laser-produced plasma sources. We present a study using seven different target materials for optimized data analysis. The emission spectra of the materials with atomic numbers ranging from Z = 6 to Z = 79 show distinct differences, rendering the adapted selection of a suitable target material for specialized experiments feasible. For NEXAFS spectroscopy a 112.5 nm thick polyimide film is investigated as a reference exemplifying the superiority of quasi-continuum like emission spectra.

Impulsive phase soft X-ray blueshifts at a loop footpoint

NASA Astrophysics Data System (ADS)

Zarro, Dominic M.; Slater, Gregory L.; Freeland, Samuel L.

1988-10-01

Solar Maximum Mission (SMM) observations of a solar flare that occurred on May 24, 1987 are described. The event was noteworthy in that it was observed during the impulsive phase with the SMM X-ray Poly-chromator (XRP) pointed at a location associated with the chromospheric footpoints of a system of coronal loops. Density-sensitive line ratios at the flare site imply an initially large electron density of 5 x 10 to the 12th/cu cm, which decreased an order of magnitude during the flare. Spectral scans of the soft X-ray Mg XI line at the site reveal asymmetric blueshifted (200 km/s) profiles concurrent with impulsive hard X-ray emission. The blueshift amplitude was correlated with the intensity of hard X-rays (with a phase delay of about 30 s) and showed fluctuations on a time scale comparable with the variation of hard X-ray emission. These observations are interpreted as evidence for chromospheric evaporation produced by heating and expansion of footpoint plasma.

Impulsive phase soft X-ray blueshifts at a loop footpoint

NASA Technical Reports Server (NTRS)

Zarro, Dominic M.; Slater, Gregory L.; Freeland, Samuel L.

1988-01-01

Solar Maximum Mission (SMM) observations of a solar flare that occurred on May 24, 1987 are described. The event was noteworthy in that it was observed during the impulsive phase with the SMM X-ray Poly-chromator (XRP) pointed at a location associated with the chromospheric footpoints of a system of coronal loops. Density-sensitive line ratios at the flare site imply an initially large electron density of 5 x 10 to the 12th/cu cm, which decreased an order of magnitude during the flare. Spectral scans of the soft X-ray Mg XI line at the site reveal asymmetric blueshifted (200 km/s) profiles concurrent with impulsive hard X-ray emission. The blueshift amplitude was correlated with the intensity of hard X-rays (with a phase delay of about 30 s) and showed fluctuations on a time scale comparable with the variation of hard X-ray emission. These observations are interpreted as evidence for chromospheric evaporation produced by heating and expansion of footpoint plasma.

Observation of soft X-ray spectra from a Seyfert 1 and a narrow emission-line galaxy

NASA Technical Reports Server (NTRS)

Singh, K. P.; Garmire, G. P.; Nousek, J.

1985-01-01

The 0.2-40 keV X-ray spectra of the Seyfert 1 galaxy Mrk 509 and the narrow emission-line galaxy NGC 2992 are analyzed. The results suggest the presence of a steep soft X-ray component in Mrk 509 in addition to the well-known Gamma = 1.7 component found in other active galactic nuclei in the 2-40 keV energy range. The soft X-ray component is interpreted as due to thermal emission from a hot gas, probably associated with the highly ionized gas observed to be outflowing from the galaxy. The X-ray spectrum of NGC 2992 does not show any steepening in the soft X-ray band and is consistent with a single power law (Gamma = 1.78) with very low absorbing column density of 4 x 10 to the 21st/sq cm. A model with partial covering of the nuclear X-ray source is preferred, however, to a simple model with a single power law and absorption.

Direct index of refraction measurements at extreme-ultraviolet and soft-x-ray wavelengths.

PubMed

Rosfjord, Kristine; Chang, Chang; Miyakawa, Ryan; Barth, Holly; Attwood, David

2006-03-10

Coherent radiation from undulator beamlines has been used to directly measure the real and imaginary parts of the index of refraction of several materials at both extreme-ultraviolet and soft-x-ray wavelengths. Using the XOR interferometer, we measure the refractive indices of silicon and ruthenium, essential materials for extreme-ultraviolet lithography. Both materials are tested at wavelength (13.4 nm) and across silicon's L2 (99.8 eV) and L3 (99.2 eV) absorption edges. We further extend this direct phase measurement method into the soft-x-ray region, where measurements of chromium and vanadium are performed around their L3 absorption edges at 574.1 and 512.1 eV, respectively. These are the first direct measurements, to our knowledge, of the real part of the index of refraction made in the soft-x-ray region.

Wide Field-of-View Soft X-Ray Imaging for Solar Wind-Magnetosphere Interactions

NASA Technical Reports Server (NTRS)

Walsh, B. M.; Collier, M. R.; Kuntz, K. D.; Porter, F. S.; Sibeck, D. G.; Snowden, S. L.; Carter, J. A.; Collado-Vega, Y.; Connor, H. K.; Cravens, T. E.;

Inelastic X-ray Scattering Studies of Plasmons in Carbon Nanotubes

NASA Astrophysics Data System (ADS)

Upton, M. H.; Klie, R. F.; Hill, J. P.; Gog, T.; Casa, D.; Ku, W.; Zhu, Y.; Sfeir, M. Y.; Misewich, J.; Eres, G.; Lowndes, D.

2007-03-01

We investigate the physical parameters controlling the low energy screening in carbon nanotubes via electron energy loss spectroscopy and inelastic x-ray scattering. Two plasmon-like features are observed, one near 9 eV (the so- called π plasmon) and one near 20 eV (the so-called π+σ plasmon). At large nanotube diameters, the π+σ plasmon energies depend exclusively on the number of walls and not on the radius or chiral vector. This shift indicates a change of strength of screening and the effective interaction at inter-atomic distance, and thus suggests an alternative mechanism of tuning the properties of the nanotube in addition to the well-known control provided by chirality and tube diameter.

A soft X-ray flare in the Seyfert I galaxy Markarian 335

NASA Technical Reports Server (NTRS)

Lee, M. G.; Balick, Bruce; Halpern, J. P.; Heckman, T. M.

1988-01-01

Strong, erratic, and primarily soft X-ray flux variations observed in Mrk 335 with the Einstein high-resolution imager (HRI) and monitor proportional counter (MPC) are reported. The variability time scales lie from about 6000 s to the period of observation, 60,000 s. The variability consisted of a decrease followed by an increase at X-ray energies below 2-3 keV. The variability is most pronounced at the softest energies. The X-ray spectrum was harder before the flare than afterward, even after the flare had ended. Averaged over the time of the observations, the MPC data are well-fitted by a power-law spectrum with a spectral index of 1.25 + or - 0.19 with no evidence of absorption by foreground neutral hydrogen at energies above 1.2 keV. If the observed value of the Galactic H I column density is assumed, then the HRI observations require the existence of an additional soft and variable X-ray component.

An extended soft X-ray source in Delphinus - H2027+19

NASA Technical Reports Server (NTRS)

Stern, R. A.; Walker, A. B. C.; Charles, P. A.; Nugent, J. J.; Garmire, G. P.

1980-01-01

A new extended soft X-ray source has been observed with the HEAO 1 A-2 experiment. The source, H2027+19, emits primarily in the 0.16-0.4 keV band with a total flux in this band of 2 x 10 to the -11th erg/sq cm s. It is found that both simple continuum and coronal plasma models provide good fits to the observed pulse-height spectrum. The most likely physical models are either that the source is an old supernova remnant or that it is a region of enhanced soft X-ray emission surrounding an H I cloud imbedded in a coronal plasma, as suggested by Hayakawa et al. (1979) for the Lupus Loop.

Design of an imaging microscope for soft X-ray applications

NASA Astrophysics Data System (ADS)

Hoover, Richard B.; Shealy, David L.; Gabardi, David R.; Walker, Arthur B. C., Jr.; Lindblom, Joakim F.

1988-01-01

An imaging soft X-ray microscope with a spatial resolution of 0.1 micron and normal incidence multilayer optics is discussed. The microscope has a Schwarzschild configuration, which consists of two concentric spherical mirrors with radii of curvature which minimize third-order spherical aberration, coma, and astigmatism. The performance of the Stanford/MSFC Cassegrain X-ray telescope and its relevance to the present microscope are addressed. A ray tracing analysis of the optical system indicates that diffraction-limited performance can be expected for an object height of 0.2 mm.

Ionized Absorbers in Active Galactic Nuclei and Very Steap Soft X-Ray Quasars

NASA Technical Reports Server (NTRS)

Fiore, Fabrizio; White, Nicholas (Technical Monitor)

2000-01-01

Steep soft X-ray (0.1-2 keV) quasars share several unusual properties: narrow Balmer lines, strong Fe II emission, large and fast X-ray variability, and a rather steep 2-10 keV spectrum. These intriguing objects have been suggested to be the analogues of Galactic black hole candidates in the high, soft state. We present here results from ASCA observations for two of these quasars: NAB 0205 + 024 and PG 1244 + 026. Both objects show similar variations (factor of approximately 2 in 10 ks), despite a factor of approximately 10 difference in the 0.5-10 keV luminosity (7.3 x 10(exp 43) erg/s for PG 1244 + 026 and 6.4 x 10(exp 44) erg/s for NAB 0205 + 024, assuming isotropic emission, H(sub 0) = 50.0 and q(sub 0) = 0.0). The X-ray continuum of the two quasars flattens by 0.5-1 going from the 0.1-2 keV band towards higher energies, strengthening recent results on another half-dozen steep soft X-ray active galactic nuclei. PG 1244 + 026 shows a significant feature in the '1-keV' region, which can be described either as a broad emission line centered at 0.95 keV (quasar frame) or as edge or line absorption at 1.17 (1.22) keV. The line emission could be a result of reflection from a highly ionized accretion disc, in line with the view that steep soft X-ray quasars are emitting close to the Eddington luminosity. Photoelectric edge absorption or resonant line absorption could be produced by gas outflowing at a large velocity (0.3-0.6 c).

Background radiation in inelastic X-ray scattering and X-ray emission spectroscopy. A study for Johann-type spectrometers

NASA Astrophysics Data System (ADS)

Paredes Mellone, O. A.; Bianco, L. M.; Ceppi, S. A.; Goncalves Honnicke, M.; Stutz, G. E.

2018-06-01

A study of the background radiation in inelastic X-ray scattering (IXS) and X-ray emission spectroscopy (XES) based on an analytical model is presented. The calculation model considers spurious radiation originated from elastic and inelastic scattering processes along the beam paths of a Johann-type spectrometer. The dependence of the background radiation intensity on the medium of the beam paths (air and helium), analysed energy and radius of the Rowland circle was studied. The present study shows that both for IXS and XES experiments the background radiation is dominated by spurious radiation owing to scattering processes along the sample-analyser beam path. For IXS experiments the spectral distribution of the main component of the background radiation shows a weak linear dependence on the energy for the most cases. In the case of XES, a strong non-linear behaviour of the background radiation intensity was predicted for energy analysis very close to the backdiffraction condition, with a rapid increase in intensity as the analyser Bragg angle approaches π / 2. The contribution of the analyser-detector beam path is significantly weaker and resembles the spectral distribution of the measured spectra. Present results show that for usual experimental conditions no appreciable structures are introduced by the background radiation into the measured spectra, both in IXS and XES experiments. The usefulness of properly calculating the background profile is demonstrated in a background subtraction procedure for a real experimental situation. The calculation model was able to simulate with high accuracy the energy dependence of the background radiation intensity measured in a particular XES experiment with air beam paths.

Experimental demonstration of a soft x-ray self-seeded free-electron laser

DOE PAGES

Ratner, D.; Abela, R.; Amann, J.; ...

2015-02-06

The Linac Coherent Light Source has added self-seeding capability to the soft x-ray range using a grating monochromator system. We report demonstration of soft x-ray self-seeding with a measured resolving power of 2000-5000, wavelength stability of 10 -4, and an increase in peak brightness by a factor of 2-5 across the photon energy range of 500-1000 eV. By avoiding the need for a monochromator at the experimental station, the self-seeded beam can deliver as much as 50 fold higher brightness to users.

Experimental demonstration of a soft x-ray self-seeded free-electron laser.

PubMed

Ratner, D; Abela, R; Amann, J; Behrens, C; Bohler, D; Bouchard, G; Bostedt, C; Boyes, M; Chow, K; Cocco, D; Decker, F J; Ding, Y; Eckman, C; Emma, P; Fairley, D; Feng, Y; Field, C; Flechsig, U; Gassner, G; Hastings, J; Heimann, P; Huang, Z; Kelez, N; Krzywinski, J; Loos, H; Lutman, A; Marinelli, A; Marcus, G; Maxwell, T; Montanez, P; Moeller, S; Morton, D; Nuhn, H D; Rodes, N; Schlotter, W; Serkez, S; Stevens, T; Turner, J; Walz, D; Welch, J; Wu, J

2015-02-06

The Linac Coherent Light Source has added a self-seeding capability to the soft x-ray range using a grating monochromator system. We report the demonstration of soft x-ray self-seeding with a measured resolving power of 2000-5000, wavelength stability of 10(-4), and an increase in peak brightness by a factor of 2-5 across the photon energy range of 500-1000 eV. By avoiding the need for a monochromator at the experimental station, the self-seeded beam can deliver as much as 50-fold higher brightness to users.

Temporal cross-correlation of x-ray free electron and optical lasers using soft x-ray pulse induced transient reflectivity.

PubMed

Krupin, O; Trigo, M; Schlotter, W F; Beye, M; Sorgenfrei, F; Turner, J J; Reis, D A; Gerken, N; Lee, S; Lee, W S; Hays, G; Acremann, Y; Abbey, B; Coffee, R; Messerschmidt, M; Hau-Riege, S P; Lapertot, G; Lüning, J; Heimann, P; Soufli, R; Fernández-Perea, M; Rowen, M; Holmes, M; Molodtsov, S L; Föhlisch, A; Wurth, W

2012-05-07

The recent development of x-ray free electron lasers providing coherent, femtosecond-long pulses of high brilliance and variable energy opens new areas of scientific research in a variety of disciplines such as physics, chemistry, and biology. Pump-probe experimental techniques which observe the temporal evolution of systems after optical or x-ray pulse excitation are one of the main experimental schemes currently in use for ultrafast studies. The key challenge in these experiments is to reliably achieve temporal and spatial overlap of the x-ray and optical pulses. Here we present measurements of the x-ray pulse induced transient change of optical reflectivity from a variety of materials covering the soft x-ray photon energy range from 500eV to 2000eV and outline the use of this technique to establish and characterize temporal synchronization of the optical-laser and FEL x-ray pulses.

Introducing a New Capability at SSRL: Resonant Soft X-ray Scattering

NASA Astrophysics Data System (ADS)

Lee, Jun-Sik; Jang, Hoyoung; Lu, Donghui; Kao, Chi-Chang

Stanford Synchrotron Radiation Lightsource (SSRL) at SLAC recently developed a setup for the resonant soft x-ray scattering (RSXS). In general, the RSXS technique uniquely probes not only structural information, but also chemical specific information. This is because this technique can explore the spatial periodicities of charge, orbital, spin, and lattice with spectroscopic aspect. Moreover, the soft x-ray range is particularly relevant for a study of soft materials as it covers the K-edge of C, N, F, and O, as well as the L-edges of transition metals and M-edges of rare-earth elements. Hence, the RSXS capability has been regarded as a very powerful technique for investigating the intrinsic properties of materials such as quantum- and energy-materials. The RSXS capability at the SSRL composes of in-vacuum 4-circle diffractometer. There are also the fully motorized sample-motion manipulations. Also, the sample can be cooled down to 25 K via the liquid helium. This capability has been installed at BL 13-3, where the photon source is from elliptically polarized undulator (EPU). Covering the photon energies is from 230 eV to 1400 eV. Furthermore, this EPU system offers more degree of freedoms for controlling x-ray polarizations (linear and circular). Using the advance of controlling x-ray polarization, we can also investigate a morphology effect of local domain/grain in materials. The detailed introduction of the RSXS end-station and several results will be touched in this poster presentation.

Implementation of Soft X-ray Tomography on NSTX

NASA Astrophysics Data System (ADS)

Tritz, K.; Stutman, D.; Finkenthal, M.; Granetz, R.; Menard, J.; Park, W.

2003-10-01

A set of poloidal ultrasoft X-ray arrays is operated by the Johns Hopkins group on NSTX. To enable MHD mode analysis independent of the magnetic reconstruction, the McCormick-Granetz tomography code developed at MIT is being adapted to the NSTX geometry. Tests of the code using synthetic data show that that present X-ray system is adequate for m=1 tomography. In addition, we have found that spline basis functions may be better suited than Bessel functions for the reconstruction of radially localized phenomena in NSTX. The tomography code was also used to determine the necessary array expansion and optimal array placement for the characterization of higher m modes (m=2,3) in the future. Initial reconstruction of experimental soft X-ray data has been performed for m=1 internal modes, which are often encountered in high beta NSTX discharges. The reconstruction of these modes will be compared to predictions from the M3D code and magnetic measurements.

Tunable Soft X-Ray Oscillators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wurtele, Jonathan; Gandhi, Punut; Gu, X-W

A concept for a tunable soft x-ray free electron laser (FEL) photon source is presented and studied numerically. The concept is based on echo-enabled harmonic generation (EEHG), wherein two modulator-chicane sections impose high harmonic structure with much greater efficacy as compared to conventional high harmonic FELs that use only one modulator-chicane section. The idea proposed here is to replace the external laser power sources in the EEHG modulators with FEL oscillators, and to combine the bunching of the beam with the production of radiation. Tunability is accomplished by adjusting the magnetic chicanes while the two oscillators remain at a fixedmore » frequency. This scheme eliminates the need to develop coherent sources with the requisite power, pulse length, and stability requirements by exploiting the MHz bunch repetition rates of FEL continuous wave (CW) sources driven by superconducting (SC) linacs. We present time-dependent GINGER simulation results for an EEHG scheme with an oscillator modulator at 43 nm employing 50percent reflective dielectric mirrors and a second modulator employing an external, 215-nm drive laser. Peak output of order 300 MW is obtained at 2.7 nm, corresponding to the 80th harmonic of 215 nm. An alternative single-cavity echo-oscillator scheme based on a 13.4 nm oscillator is investigated with time-independent simulations that a 180-MW peak power at final wavelength of 1.12 nm. Three alternate configurations that use separate bunches to produce the radiation for EEHG microbunching are also presented. Our results show that oscillator-based soft x-ray FELs driven by CWSC linacs are extremely attractive because of their potential to produce tunable radiation at high average power together with excellent longitudinal coherence and narrow spectral bandwidth.« less

A new streaked soft x-ray imager for the National Ignition Facility

DOE PAGES

Benstead, J.; Moore, A. S.; Ahmed, M. F.; ...

2016-05-27

Here, a new streaked soft x-ray imager has been designed for use on high energy-density (HED) physics experiments at the National Ignition Facility based at the Lawrence Livermore National Laboratory. This streaked imager uses a slit aperture, single shallow angle reflection from a nickel mirror, and soft x-ray filtering to, when coupled to one of the NIF’s x-ray streak cameras, record a 4× magnification, one-dimensional image of an x-ray source with a spatial resolution of less than 90 μm. The energy band pass produced depends upon the filter material used; for the first qualification shots, vanadium and silver-on-titanium filters weremore » used to gate on photon energy ranges of approximately 300–510 eV and 200–400 eV, respectively. A two-channel version of the snout is available for x-ray sources up to 1 mm and a single-channel is available for larger sources up to 3 mm. Both the one and two-channel variants have been qualified on quartz wire and HED physics target shots.« less

Liquid Dynamics in high melting materials studied by inelastic X-ray scattering

NASA Astrophysics Data System (ADS)

Sinn, Harald; Alatas, Ahmet; Said, Ayman; Alp, Esen E.; Price, David L.; Saboungi, Marie Louis; Scheunemann, Richard

2004-03-01

The transport properties of high melting materials are of interest for a variety of applications, including geo-sciences, nuclear waste confinement and aerospace technology. While traditional methods of measuring transport properties are often extremely difficult due to the high reactivity of the melts, the combination of containerless levitation and inelastic X-ray scattering offers new insights in the microscopic dynamics of these liquids. Data on the dynamic structure factor of liquid aluminum oxide and liquid boron between 2000-2800 degree Celsius are discussed and related to several macroscopic quantities like sound velocity, viscosity and diffusion.

The Astro-H Soft X-Ray Mirror

NASA Technical Reports Server (NTRS)

Robinson, David; Okajima, Takashi; Serlemitsos, Peter; Soong, Yang

2012-01-01

The Astro-H is led by the Japanese Space Agency (JAXA) in collaboration with many other institutions including the NASA Goddard Space Flight Center. Goddard's contributions include two soft X-ray telescopes (SXTs). The telescopes have an effective area of 562 square cm at 1 keV and 425 square cm at 6 keV with an image quality requirement of 1.7 arc-minutes half power diameter (HPD). The engineering model has demonstrated 1.1 arc-minutes HPD error. The design of the SXT is based on the successful Suzaku mission mirrors with some enhancements to improve the image quality. Two major enhancements are bonding the X-ray mirror foils to alignment bars instead of allowing the mirrors to float, and fabricating alignment bars with grooves within 5 microns of accuracy. An engineering model SXT was recently built and subjected to several tests including vibration, thermal, and X-ray performance in a beamline. Several lessons were learned during this testing that will be incorporated in the flight design. Test results and optical performance are discussed, along with a description of the design of the SXT.

The soft x ray halo of the spiral galaxy NGC4631

NASA Technical Reports Server (NTRS)

Walterbos, Rene A. M.; Steakley, Michael F.; Wang, Q. Daniel; Norman, Colin A.; Braun, Robert

1994-01-01

ROSAT PSPC observations of the close to edge-on spiral galaxy NGC4631 are presented. This vigorously star forming galaxy shows extented x ray emission perpendicular to the plane, out to about 6 to 8 kpc. The spatial extent is largest at soft x ray energies. The total x ray luminosity of hot gas can be easily supplied by star formation in the disk, and it is likely that the halo is due to outflow of hot gas from the inner disk. Spectral analysis of the x ray data shows that part of the halo emission may be quite cool, well below 10(exp 6)K. Implications of these results are briefly discussed.

Development of a spectro-electrochemical cell for soft X-ray photon-in photon-out spectroscopy

NASA Astrophysics Data System (ADS)

Ishihara, Tomoko; Tokushima, Takashi; Horikawa, Yuka; Kato, Masaru; Yagi, Ichizo

2017-10-01

We developed a spectro-electrochemical cell for X-ray absorption and X-ray emission spectroscopy, which are element-specific methods to study local electronic structures in the soft X-ray region. In the usual electrochemical measurement setup, the electrode is placed in solution, and the surface/interface region of the electrode is not normally accessible by soft X-rays that have low penetration depth in liquids. To realize soft X-ray observation of electrochemical reactions, a 15-nm-thick Pt layer was deposited on a 150-nm-thick film window with an adhesive 3-nm-thick Ti layer for use as both the working electrode and the separator window between vacuum and a sample liquid under atmospheric pressure. The designed three-electrode electrochemical cell consists of a Pt film on a SiC window, a platinized Pt wire, and a commercial Ag|AgCl electrode as the working, counter, and reference electrodes, respectively. The functionality of the cell was tested by cyclic voltammetry and X-ray absorption and emission spectroscopy. As a demonstration, the electroplating of Pb on the Pt/SiC membrane window was measured by X-ray absorption and real-time monitoring of fluorescence intensity at the O 1s excitation.

SMM hard X-ray observations of the soft gamma-ray repeater 1806-20

NASA Technical Reports Server (NTRS)

Kouveliotou, C.; Norris, J. P.; Cline, T. L.; Dennis, B. R.; Desai, U. D.; Orwig, L. E.

1987-01-01

Six bursts from the soft gamma-ray repeater (SGR) 1806-20 have been recorded with the SMM Hard X-ray Burst Spectrometer during a highly active phase in 1983. Rise and decay times of less than 5 ns have been detected. Time profiles of these events indicate low-level emission prior to and after the main peaks. The results suggest that SGRs are distinguished from classical gamma-ray bursts by repetition, softer nonvarying spectra, short durations, simple temporal profiles, and a tendency for source locations to correlate with Population I objects. SGR characteristics differ from those of type I X-ray bursts, but they appear to have similarities with the type II bursts from the Rapid Burster.

Aplanatic Three-Mirror Objective for High-Magnification Soft X-Ray Microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Toyoda, M.; Jinno, T.; Yanagihara, M.

2011-09-09

An innovative solution for high-magnification microscopy, based on attaching afocal optics for focal length reduction, is proposed. The solution, consisting of three spherical mirrors, allows one to enhance a magnification of a laboratory based soft x-ray microscope over 1000x, where movies with diffraction-limited resolution can be observed with an x-ray CCD. The design example, having a numerical aperture of 0.25, was successfully demonstrated both a high magnification and a large field of view.

The SMILE Soft X-ray Imager (SXI) CCD design and development

NASA Astrophysics Data System (ADS)

Soman, M. R.; Hall, D. J.; Holland, A. D.; Burgon, R.; Buggey, T.; Skottfelt, J.; Sembay, S.; Drumm, P.; Thornhill, J.; Read, A.; Sykes, J.; Walton, D.; Branduardi-Raymont, G.; Kennedy, T.; Raab, W.; Verhoeve, P.; Agnolon, D.; Woffinden, C.

2018-01-01

SMILE, the Solar wind Magnetosphere Ionosphere Link Explorer, is a joint science mission between the European Space Agency and the Chinese Academy of Sciences. The spacecraft will be uniquely equipped to study the interaction between the Earth's magnetosphere-ionosphere system and the solar wind on a global scale. SMILE's instruments will explore this science through imaging of the solar wind charge exchange soft X-ray emission from the dayside magnetosheath, simultaneous imaging of the UV northern aurora and in-situ monitoring of the solar wind and magnetosheath plasma and magnetic field conditions. The Soft X-ray Imager (SXI) is the instrument being designed to observe X-ray photons emitted by the solar wind charge exchange process at photon energies between 200 eV and 2000 eV . X-rays will be collected using a focal plane array of two custom-designed CCDs, each consisting of 18 μm square pixels in a 4510 by 4510 array. SMILE will be placed in a highly elliptical polar orbit, passing in and out of the Earth's radiation belts every 48 hours. Radiation damage accumulated in the CCDs during the mission's nominal 3-year lifetime will degrade their performance (such as through decreases in charge transfer efficiency), negatively impacting the instrument's ability to detect low energy X-rays incident on the regions of the CCD image area furthest from the detector outputs. The design of the SMILE-SXI CCDs is presented here, including features and operating methods for mitigating the effects of radiation damage and expected end of life CCD performance. Measurements with a PLATO device that has not been designed for soft X-ray signal levels indicate a temperature-dependent transfer efficiency performance varying between 5×10-5 and 9×10-4 at expected End of Life for 5.9 keV photons, giving an initial set of measurements from which to extrapolate the performance of the SXI CCDs.

0.5-keV Soft X-ray attosecond continua

PubMed Central

Teichmann, S. M.; Silva, F.; Cousin, S. L.; Hemmer, M.; Biegert, J.

2016-01-01

Attosecond light pulses in the extreme ultraviolet have drawn a great deal of attention due to their ability to interrogate electronic dynamics in real time. Nevertheless, to follow charge dynamics and excitations in materials, element selectivity is a prerequisite, which demands such pulses in the soft X-ray region, above 200 eV, to simultaneously cover several fundamental absorption edges of the constituents of the materials. Here, we experimentally demonstrate the exploitation of a transient phase matching regime to generate carrier envelope controlled soft X-ray supercontinua with pulse energies up to 2.9±0.1 pJ and a flux of (7.3±0.1) × 107 photons per second across the entire water window and attosecond pulses with 13 as transform limit. Our results herald attosecond science at the fundamental absorption edges of matter by bridging the gap between ultrafast temporal resolution and element specific probing. PMID:27167525

Development of ultrahigh-resolution inelastic x-ray scattering optics

NASA Astrophysics Data System (ADS)

Huang, Xian-Rong; Zhong, Zhong; Cai, Yong Q.; Coburn, S.

2008-08-01

One of the major goals of the National Synchrotron Light Source II project is to achieve ultrahigh energy resolution up to 0.1 meV for medium-energy inelastic X-ray scattering spectroscopy based on the angular dispersion optics employing extremely asymmetric backscattering geometry. In this papaer, we describe the complete monochromatization mechanisms underlying the new optics. We have also designed and tested a CDW-CDW prototype under ambient condition, with which we have successfully demonstrated the important angular dispersion effect, the Borrman enhanced transmission effect, and other optical principles involved in every step of the entire diffraction process, and found good agreement with the theoretical expectations. These studies indicate that the new optics are feasible in principle but face some technical challenges that need to be solved by our future systematic research and development activities before their practical applications.

Soft x-ray submicron imaging detector based on point defects in LiF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baldacchini, G.; Bollanti, S.; Bonfigli, F.

2005-11-15

The use of lithium fluoride (LiF) crystals and films as imaging detectors for EUV and soft-x-ray radiation is discussed. The EUV or soft-x-ray radiation can generate stable color centers, emitting in the visible spectral range an intense fluorescence from the exposed areas. The high dynamic response of the material to the received dose and the atomic scale of the color centers make this detector extremely interesting for imaging at a spatial resolution which can be much smaller than the light wavelength. Experimental results of contact microscopy imaging of test meshes demonstrate a resolution of the order of 400 nm. Thismore » high spatial resolution has been obtained in a wide field of view, up to several mm{sup 2}. Images obtained on different biological samples, as well as an investigation of a soft x-ray laser beam are presented. The behavior of the generated color centers density as a function of the deposited x-ray dose and the advantages of this new diagnostic technique for both coherent and noncoherent EUV sources, compared with CCDs detectors, photographic films, and photoresists are discussed.« less

Band gap states in nanocrystalline WO3 thin films studied by soft x-ray spectroscopy and optical spectrophotometry.

PubMed

Johansson, M B; Kristiansen, P T; Duda, L; Niklasson, G A; Österlund, L

2016-11-30

Nanocrystalline tungsten trioxide (WO3) thin films prepared by DC magnetron sputtering have been studied using soft x-ray spectroscopy and optical spectrophotometry. Resonant inelastic x-ray scattering (RIXS) measurements reveal band gap states in sub-stoichiometric γ-WO3-x with x  =  0.001-0.005. The energy positions of these states are in good agreement with recently reported density functional calculations. The results were compared with optical absorption measurements in the near infrared spectral region. An optical absorption peak at 0.74 eV is assigned to intervalence transfer of polarons between W sites. A less prominent peak at energies between 0.96 and 1.16 eV is assigned to electron excitation of oxygen vacancies. The latter results are supported by RIXS measurements, where an energy loss in this energy range was observed, and this suggests that electron transfer processes involving transitions from oxygen vacancy states can be observed in RIXS. Our results have implications for the interpretation of optical properties of WO3, and the optical transitions close to the band gap, which are important in photocatalytic and photoelectrochemical applications.

Multilayer on-chip stacked Fresnel zone plates: Hard x-ray fabrication and soft x-ray simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Kenan; Wojcik, Michael J.; Ocola, Leonidas E.

2015-11-01

Fresnel zone plates are widely used as x-ray nanofocusing optics. To achieve high spatial resolution combined with good focusing efficiency, high aspect ratio nanolithography is required, and one way to achieve that is through multiple e-beam lithography writing steps to achieve on-chip stacking. A two-step writing process producing 50 nm finest zone width at a zone thickness of 1.14 µm for possible hard x-ray applications is shown here. The authors also consider in simulations the case of soft x-ray focusing where the zone thickness might exceed the depth of focus. In this case, the authors compare on-chip stacking with, andmore » without, adjustment of zone positions and show that the offset zones lead to improved focusing efficiency. The simulations were carried out using a multislice propagation method employing Hankel transforms.« less

FPGA based charge acquisition algorithm for soft x-ray diagnostics system

NASA Astrophysics Data System (ADS)

Wojenski, A.; Kasprowicz, G.; Pozniak, K. T.; Zabolotny, W.; Byszuk, A.; Juszczyk, B.; Kolasinski, P.; Krawczyk, R. D.; Zienkiewicz, P.; Chernyshova, M.; Czarski, T.

2015-09-01

Soft X-ray (SXR) measurement systems working in tokamaks or with laser generated plasma can expect high photon fluxes. Therefore it is necessary to focus on data processing algorithms to have the best possible efficiency in term of processed photon events per second. This paper refers to recently designed algorithm and data-flow for implementation of charge data acquisition in FPGA. The algorithms are currently on implementation stage for the soft X-ray diagnostics system. In this paper despite of the charge processing algorithm is also described general firmware overview, data storage methods and other key components of the measurement system. The simulation section presents algorithm performance and expected maximum photon rate.

Soft X-ray scanning transmission X-ray microscopy (STXM) of actinide particles.

PubMed

Nilsson, Hans J; Tyliszczak, Tolek; Wilson, Richard E; Werme, Lars; Shuh, David K

2005-09-01

A descriptive account is given of our most recent research on the actinide dioxides with the Advanced Light Source Molecular Environmental Science (ALS-MES) Beamline 11.0.2 soft X-ray scanning transmission X-ray microscope (STXM) at the Lawrence Berkeley National Laboratory (LBNL). The ALS-MES STXM permits near-edge X-ray absorption fine structure (NEXAFS) and imaging with 30-nm spatial resolution. The first STXM spectromicroscopy NEXAFS spectra at the actinide 4d5/2 edges of the imaged transuranic particles, NpO2 and PuO2, have been obtained. Radiation damage induced by the STXM was observed in the investigation of a mixed oxidation state particle (Np(V,VI)) and was minimized during collection of the actual spectra at the 4d5/2 edge of the Np(V,VI) solid. A plutonium elemental map was obtained from an irregular PuO2 particle with the dimensions of 650 x 650 nm. The Pu 4d5/2 NEXAFS spectra were collected at several different locations from the PuO2 particle and were identical. A representative oxygen K-edge spectrum from UO2 was collected and resembles the oxygen K-edge from the bulk material. The unique and current performance of the ALS-MES STXM at extremely low energies (ca. 100 eV) that may permit the successful measurement of the actinide 5d edge is documented. Finally, the potential of STXM as a tool for actinide investigations is briefly discussed.

Impulsive phase soft X-ray blueshifts at a loop footpoint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zarro, D.M.; Slater, G.L.; Freeland, S.L.

Solar Maximum Mission (SMM) observations of a solar flare that occurred on May 24, 1987 are described. The event was noteworthy in that it was observed during the impulsive phase with the SMM X-ray Poly-chromator (XRP) pointed at a location associated with the chromospheric footpoints of a system of coronal loops. Density-sensitive line ratios at the flare site imply an initially large electron density of 5 x 10 to the 12th/cu cm, which decreased an order of magnitude during the flare. Spectral scans of the soft X-ray Mg XI line at the site reveal asymmetric blueshifted (200 km/s) profiles concurrentmore » with impulsive hard X-ray emission. The blueshift amplitude was correlated with the intensity of hard X-rays (with a phase delay of about 30 s) and showed fluctuations on a time scale comparable with the variation of hard X-ray emission. These observations are interpreted as evidence for chromospheric evaporation produced by heating and expansion of footpoint plasma. 13 references.« less

The Variable Fast Soft X-Ray Wind in PG 1211+143

NASA Astrophysics Data System (ADS)

Reeves, J. N.; Lobban, A.; Pounds, K. A.

2018-02-01

The analysis of a series of seven observations of the nearby (z = 0.0809) QSO PG 1211+143, taken with the Reflection Grating Spectrometer (RGS) onboard XMM-Newton in 2014, are presented. The high-resolution soft X-ray spectrum, with a total exposure exceeding 600 ks, shows a series of blueshifted absorption lines from the He and H-like transitions of N, O, and Ne, as well as from L-shell Fe. The strongest absorption lines are all systematically blueshifted by ‑0.06c, originating in two absorption zones from low- and high-ionization gas. Both zones are variable on timescales of days, with the variations in absorber opacity effectively explained by either column density changes or the absorber ionization responding directly to the continuum flux. We find that the soft X-ray absorbers probably exist in a two-phase wind at a radial distance of ∼1017–1018 cm from the black hole with the lower-ionization gas as denser clumps embedded within a higher-ionization outflow. The overall mass outflow rate of the soft X-ray wind may be as high as 2{M}ȯ yr‑1, close to the Eddington rate for PG 1211+143 and similar to that previously deduced from the Fe K absorption.

Design of High Resolution Soft X-Ray Microcalorimeters Using Magnetic Penetration Thermometers

NASA Technical Reports Server (NTRS)

Busch. Sarah; Balvin, Manuel; Bandler, Simon; Denis, Kevin; Finkbeiner, Fred; Porst, Jan-Patrick; Sadlier, Jack; Smith, Stephen; Stevenson, Thomas

2012-01-01

We have designed high-resolution soft x-ray microcalorimeters using magnetic penetration thermometers (MPTs) in an array of pixels covering a total of 2 square centimeters to have a resolving power of 300 at energies around 300 eV. This performance is desirable for studying the soft x-ray background from the warm hot intergalactic medium. MPT devices have small sensor heat capacity and high responsivities, which makes them excellent detector technology for attempting to attain sub-eV resolution. We are investigating the feasibility of pixels with absorbers that are 625 x 625 square micrometers, up to 1 x 1 square millimeters in area and 0.35 micrometer thick and thinner. Our tests have shown that suspended gold absorbers 0.35 micrometers thick (RRR = 6.7) are feasible to fabricate. We modeled the thermal diffusion from such thin gold over the size of a 625 x 625 square micrometer absorber, and conclude that the effect of the thermalization on the resolution of a 300 eV photon is an additional approximately 0.2 eV FWHM of broadening. We discuss the thermal effects of small absorber attachment sterns on solid substrate, as well as considerations for multiplexed readout. We will present the progress we have made towards building and testing this soft x-ray detector.

Multiplexed high resolution soft x-ray RIXS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chuang, Y.-D.; Voronov, D.; Warwick, T.

2016-07-27

High-resolution Resonance Inelastic X-ray Scattering (RIXS) is a technique that allows us to probe the electronic excitations of complex materials with unprecedented precision. However, the RIXS process has a low cross section, compounded by the fact that the optical spectrometers used to analyze the scattered photons can only collect a small solid angle and overall have a small efficiency. Here we present a method to significantly increase the throughput of RIXS systems, by energy multiplexing, so that a complete RIXS map of scattered intensity versus photon energy in and photon energy out can be recorded simultaneously{sup 1}. This parallel acquisitionmore » scheme should provide a gain in throughput of over 100.. A system based on this principle, QERLIN, is under construction at the Advanced Light Source (ALS).« less

Imaging performance of a normal incidence soft X-ray telescope

NASA Technical Reports Server (NTRS)

Henry, J. P.; Spiller, E.; Weisskopf, M.

1982-01-01

Measurements are presented of the imaging performance of a normal incidence spherical soft X-ray mirror at BK-alpha (67.6 A). The reflector was a 124-layer coating consisting of alternating Re-W alloy and C layers with a protective C overcoat 34 A thick deposited on a Zerodur substrate. Measurements made at an angle of 1.5 deg off axis with the prototype of the Einstein Observatory high resolution imager reveal the resolution of the mirror to be about 1 arcsec FWHM, with 50% of the reflected power within the detector field of 512 arcsec contained within a diameter of 5 arcsec. The data demonstrate the practicality and potential good performance of normal-incidence soft X-ray optics, and show that the scattering performances of such devices may be as good or better than the best grazing incidence devices.

Soft X-ray maps of the Large Magellanic Cloud (LMC)

NASA Technical Reports Server (NTRS)

Singh, K. P.; Nousek, J. A.; Burrows, D. N.; Garmire, G. P.

1985-01-01

Soft X-ray maps of the Large Magellanic Cloud (LMC) were obtained from scanning-observations with the HEAO-1 low energy detectors. Comparison of the 1/4 keV X-ray observations with the neutral hydrogen column densities in the LMC obtained from a 21 cm line survey, shows no evidence for absorption effects in the 1/4 keV X-ray flux from the LMC due to the neutral matter in the LMC. Instead, faint X-ray emission is detected from the LMC. The extent of this emission is smaller than the size of the halo or the disk of the LMC. Assuming this 1/4 keV emission to be diffuse, it is identified with a supergiant shell of optical nebulosity known as Shapley III, and the bar of the LMC. The X-ray luminosities of the regions are estimated to be 9 times 10 to the 38th power ergs/sec and 1.8 times 10 to the 39th power ergs/sec for the Shapley III region and the bar of the LMC respectively. Shapley III could be an X-ray superbubble.

Soft X-Ray Irradiation of Silicates: Implications for Dust Evolution in Protoplanetary Disks

NASA Astrophysics Data System (ADS)

Ciaravella, A.; Cecchi-Pestellini, C.; Chen, Y.-J.; Muñoz Caro, G. M.; Huang, C.-H.; Jiménez-Escobar, A.; Venezia, A. M.

2016-09-01

The processing of energetic photons on bare silicate grains was simulated experimentally on silicate films submitted to soft X-rays of energies up to 1.25 keV. The silicate material was prepared by means of a microwave assisted sol-gel technique. Its chemical composition reflects the Mg2SiO4 stoichiometry with residual impurities due to the synthesis method. The experiments were performed using the spherical grating monochromator beamline at the National Synchrotron Radiation Research Center in Taiwan. We found that soft X-ray irradiation induces structural changes that can be interpreted as an amorphization of the processed silicate material. The present results may have relevant implications in the evolution of silicate materials in X-ray-irradiated protoplanetary disks.

Molybdenum X-Ray Absorption Edges from 200 – 20,000 eV, The Benefits of Soft X-Ray Spectroscopy for Chemical Speciation

PubMed Central

George, Simon J.; Drury, Owen B.; Fu, Juxia; Friedrich, Stephan; Doonan, Christian J.; George, Graham N.; White, Jonathan M.; Young, Charles G.; Cramer, Stephen P.

2009-01-01

We have surveyed the chemical utility of the near-edge structure of molybdenum x-ray absorption edges from the hard x-ray K-edge at 20,000 eV down to the soft x-ray M4,5-edges at ~230 eV. We compared, for each edge, the spectra of two tetrahedral anions, MoO4 and MoS42-. We used three criteria for assessing near-edge structure of each edge: (i) the ratio of the observed chemical shift between MoO42- and MoS42- and the linewidth, (ii) the chemical information from analysis of the near-edge structure and (iii) the ease of measurement using fluorescence detection. Not surprisingly, the K-edge was by far the easiest to measure, but it contained the least information. The L2,3-edges, although harder to measure, had benefits with regard to selection rules and chemical speciation in that they had both a greater chemical shift as well as detailed lineshapes which could be theoretically analyzed in terms of Mo ligand field, symmetry, and covalency. The soft x-ray M2,3-edges were perhaps the least useful, in that they were difficult to measure using fluorescence detection and had very similar information content to the corresponding L2,3-edges. Interestingly, the soft x-ray, low energy (~230 eV) M4,5-edges had greatest potential chemical sensitivity and using our high resolution superconducting tunnel junction (STJ) fluorescence detector they appear to be straightforward to measure. The spectra were amenable to analysis using both the TT-multiplet approach and FEFF. The results using FEFF indicate that the sharp near-edge peaks arise from 3d → 5p transitions, while the broad edge structure has predominately 3d → 4f character. A proper understanding of the dependence of these soft x-ray spectra on ligand field and site geometry is necessary before a complete assessment of the utility of the Mo M4,5-edges can be made. This work includes crystallographic characterization of sodium tetrathiomolybdate. PMID:19041140

The Soft X-ray Spectrophotometer SphinX for the CORONAS-Photon Mission

NASA Astrophysics Data System (ADS)

Sylwester, Janusz; Kowalinski, Miroslaw; Szymon, Gburek; Bakala, Jaroslaw; Kuzin, Sergey; Kotov, Yury; Farnik, Frantisek; Reale, Fabio

The purpose, construction details and calibration results of the new design, Polish-led solar X-ray spectrophotometer SphinX will be presented. The instrument constitutes a part of the Russian TESIS X-ray and EUV complex aboard the forthcoming CORONAS-Photon solar mission to be launched later in 2008. SphinX uses Si-PIN detectors for high time resolution (down to 0.01 s) measurements of solar spectra in the energy range between 0.5 keV and 15 keV. The spectral resolution allows separating 256 individual energy channels in this range with particular groups of lines clearly distinguishable. Unprecedented accuracy of the instrument calibration at the XACT (Palermo) and BESSY (Berlin) synchrotron will allow for establishing the solar soft X-ray photometric reference system. The cross-comparison between SphinX and the other instruments presently in orbit like XRT on Hinode, RHESSI and GOES X-ray monitor, will allow for a precise determination of the coronal emission measure and temperature during both very low and very high activity periods. Examples of the detectors' ground calibration results as well as the calculated synthetic spectra will be presented. The operation of the instrument while in orbit will be discussed allowing for suggestions from other groups to be still included in mission planning.

Soft X-ray variability over the present minimum of solar activity as observed by SphinX

NASA Astrophysics Data System (ADS)

Gburek, S.; Siarkowski, M.; Kepa, A.; Sylwester, J.; Kowalinski, M.; Bakala, J.; Podgorski, P.; Kordylewski, Z.; Plocieniak, S.; Sylwester, B.; Trzebinski, W.; Kuzin, S.

2011-04-01

Solar Photometer in X-rays (SphinX) is an instrument designed to observe the Sun in X-rays in the energy range 0.85-15.00 keV. SphinX is incorporated within the Russian TESIS X and EUV telescope complex aboard the CORONAS-Photon satellite which was launched on January 30, 2009 at 13:30 UT from the Plesetsk Cosmodrome, northern Russia. Since February, 2009 SphinX has been measuring solar X-ray radiation nearly continuously. The principle of SphinX operation and the content of the instrument data archives is studied. Issues related to dissemination of SphinX calibration, data, repository mirrors locations, types of data and metadata are discussed. Variability of soft X-ray solar flux is studied using data collected by SphinX over entire mission duration.

High-energy magnetic excitations in overdoped La 2-xSr xCuO 4 studied by neutron and resonant inelastic X-ray scattering

DOE PAGES

Wakimoto, S.; Ishii, K.; Kimura, H.; ...

2015-05-21

We have performed neutron inelastic scattering and resonant inelastic x-ray scattering (RIXS) at the Cu-L 3 edge to study high-energy magnetic excitations at energy transfers of more than 100 meV for overdoped La 2₋xSr xCuO 4 with x=0.25 (T c=15 K) and x=0.30 (nonsuperconducting) using identical single-crystal samples for the two techniques. From constant-energy slices of neutron-scattering cross sections, we have identified magnetic excitations up to ~250 meV for x=0.25. Although the width in the momentum direction is large, the peak positions along the (π,π) direction agree with the dispersion relation of the spin wave in the nondoped La 2CuOmore » 4 (LCO), which is consistent with the previous RIXS results of cuprate superconductors. Using RIXS at the Cu-L 3 edge, we have measured the dispersion relations of the so-called paramagnon mode along both (π,π) and (π,0) directions. Although in both directions the neutron and RIXS data connect with each other and the paramagnon along (π,0) agrees well with the LCO spin-wave dispersion, the paramagnon in the (π,π) direction probed by RIXS appears to be less dispersive and the excitation energy is lower than the spin wave of LCO near (π/2,π/2). Thus, our results indicate consistency between neutron inelastic scattering and RIXS, and elucidate the entire magnetic excitation in the (π,π) direction by the complementary use of two probes. The polarization dependence of the RIXS profiles indicates that appreciable charge excitations exist in the same energy range of magnetic excitations, reflecting the itinerant character of the overdoped sample. Lastly, we find a possible anisotropy in the charge excitation intensity might explain the apparent differences in the paramagnon dispersion in the (π,π) direction as detected by the x-ray scattering.« less

Soft x-ray holography and microscopy of biological cells

NASA Astrophysics Data System (ADS)

Chen, Jianwen; Gao, Hongyi; Xie, Honglan; Li, Ruxin; Xu, Zhizhan

2003-10-01

Some experimental results on soft X-ray microscopy and holography imaging of biological specimens are presented in the paper. As we know, due to diffraction effects, there exists a resolution limit determined by wavelength λ and numerical aperture NA in conventional optical microscopy. In order to improve resolution, the num erical aperture should be made as large as possible and the wavelength as short as possible. Owing to the shorter wavelength, X-rays provide the potential of higher resolution in X-ray microscopy, holography image and allow for exam ination the interior structures of thicker specimens. In the experiments, we used synchrotron radiation source in Hefei as light source. Soft X-rays come from a bending magnet in 800 M eV electron storage ring with characteristic wavelength of 2.4 nm. The continuous X-ray spectrums are monochromatized by a zone-plate and a pinhole with 300 m diameter. The experimental set-up is typical contact microscopic system, its main advantage is simplicity and no special optical element is needed. The specimens used in the experiments of microscopic imaging are the colibacillus, the gingko vascular hundle and the fritillaries ovary karyon. The specimen for holographic imaging is the spider filam ents. The basic structures of plant cells such as the cell walls, the cytoplasm and the karyon especially the joint structures between the cells are observed clearly. An experimental study on a thick biological specimen that is a whole sporule w ith the thickness of about 30 μm is performed. In the holographic experiments, the experimental setup is typical Gabor in-line holography. The specimen is placed in line with X-ray source, which provides both the reference w aves and specimen illum ination. The specimen is some spider filament, which adhere to a Si3N4 film. The recording medium is PM M A, which is placed at recording distance of about 400 μm from the specimen. The hologram s were reconstructed by digital method with 300 nm

Irreversible metal-insulator transition in thin film VO2 induced by soft X-ray irradiation

NASA Astrophysics Data System (ADS)

Singh, V. R.; Jovic, V.; Valmianski, I.; Ramirez, J. G.; Lamoureux, B.; Schuller, Ivan K.; Smith, K. E.

2017-12-01

In this study, we show the ability of soft x-ray irradiation to induce room temperature metal-insulator transitions (MITs) in VO2 thin films grown on R-plane sapphire. The ability of soft x-rays to induce MIT in VO2 thin films is confirmed by photoemission spectroscopy and soft x-ray spectroscopy measurements. When irradiation was discontinued, the systems do not return to the insulating phase. Analysis of valence band photoemission spectra revealed that the density of states (DOSs) of the V 3d band increased with irradiation time, while the DOS of the O 2p band decreased. We use these results to propose a model in which the MIT is driven by oxygen desorption from thin films during irradiation.

NLTE Model Atmospheres for Super-Soft X-ray Sources

NASA Astrophysics Data System (ADS)

Rauch, Thomas; Werner, Klaus

2009-09-01

Spectral analysis by means of fully line-blanketed Non-LTE model atmospheres has arrived at a high level of sophistication. The Tübingen NLTE Model Atmosphere Package (TMAP) is used to calculate plane-parallel NLTE model atmospheres which are in radiative and hydrostatic equilibrium. Although TMAP is not especially designed for the calculation of burst spectra of novae, spectral energy distributions (SEDs) calculated from TMAP models are well suited e.g. for abundance determinations of Super Soft X-ray Sources like nova V4743 Sgr or line identifications in observations of neutron stars with low magnetic fields in low-mass X-ray binaries (LMXBs) like EXO 0748-676.

Inelastic X-ray Scattering Measurements of Ionization in Warm, Dense Matter

NASA Astrophysics Data System (ADS)

Davis, Paul F.

In this work we demonstrate spectrally resolved x-ray scattering from electron-plasma waves in shock-compressed deuterium and proton-heated matter. Because the spectral signature of inelastic x-ray scattering is strongly dependent on the free electron density of the system, it is used to infer ionization in dynamically heated samples. Using 2-6 ns, 500 J laser pulses from LLNL's Janus laser, we shocked liquid deuterium to pressures approaching 50 GPa, reaching compressions of 4 times liquid density. A second laser produced intense 2 keV x-rays. By collecting and spectrally dispersing forward scattered photons at 45°, the onset of ionization was detected at compressions of about 3 times in the form of plasmon oscillations. Backscattered x-rays bolstered this observation by measuring the free electron distribution through Compton scattering. Comparison with simulations shows very close agreement between the pressure dependence of ionization and molecular dissociation in dynamically compressed deuterium. In a second set of experiments, a 10 ps, 200 J Titan laser pulse was split into two beams. One created a stream of MeV protons to heat samples of boron and boron-nitride and the other pumped 4.5 keV K-alpha radiation in a titanium foil to probe the hot target. We observed scattered x-rays 300 ps after heating, noting a strong difference in average ionization between the two target materials at temperatures of 16 eV and very similar mass densities. Comparison with electron structure calculations suggests that this difference is due to a persistence of long-range ion structure in BN resulting in high-temperature band structure. These results underscore the importance of understanding the complex electron structure of materials even at electron-volt temperatures and gigapascal pressures. Our results provide new data to guide the theoretical modeling of warm, dense matter important to understanding giant planets and inertial fusion targets.

Generation of the Submicron Soft X-Ray Beam Using a Fresnel Zone Plate

NASA Astrophysics Data System (ADS)

Nishikino, M.; Kawazome, H.; Tanaka, M.; Kishimoto, M.; Hasegawa, N.; Ochi, Y.; Kawachi, T.; Sukegawa, K.; Yamatani, H.; Nagashima, K.; Kato, Y.

We have developed a fully coherent x-ray laser at 13.9 nm and the application research has been started. The generation of submicron x-ray beam is important for the application of high intensity x-ray beam, such as the non-linear optics, the material science, and the biology. The submicron x-ray bee am is generated by the soft x-ray laser with using a Fresnel zone plate. The spot diameter is estimated about 680 nm (290 nm at FWHM) by the theoretical calculation. In this experiment, the diameter of the x-ray beam is measured by the knife-edge scan. The diameter and the intensity are estimated 730 nm (310 nm at FWHM) and 3x1011 W/cm2, respectively.

Soft X-ray characterisation of the long-term properties of supergiant fast X-ray transients

NASA Astrophysics Data System (ADS)

Romano, P.; Ducci, L.; Mangano, V.; Esposito, P.; Bozzo, E.; Vercellone, S.

2014-08-01

Context. Supergiant fast X-ray transients (SFXTs) are high mass X-ray binaries (HMXBs) that are characterised by a hard X-ray (≥ 15 keV) flaring behaviour. These flares reach peak luminosities of 1036-1037 erg s-1 and last a few hours in the hard X-rays. Aims: We investigate the long-term properties of SFXTs by examining the soft (0.3-10 keV) X-ray emission of the three least active SFXTs in the hard X-ray and by comparing them with the remainder of the SFXT sample. Methods: We performed the first high-sensitivity soft X-ray long-term monitoring with Swift/XRT of three relatively unexplored SFXTs, IGR J08408-4503, IGR J16328-4726, and IGR J16465-4507, whose hard X-ray duty cycles are the lowest measured among the SFXT sample. We assessed how long each source spends in each flux state and compared their properties with those of the prototypical SFXTs. Results: The behaviour of IGR J08408-4503 and IGR J16328-4726 resembles that of other SFXTs, and it is characterised by a relatively high inactivity duty cycle (IDC) and pronounced dynamic range (DR) in the X-ray luminosity. We found DR ~ 7400, IDC ~ 67% for IGR J08408-4503, and DR ~ 750, IDC ~ 61% for IGR J16328-4726 (in all cases the IDC is given with respect to the limiting flux sensitivity of XRT, that is 1-3 × 10-12 erg cm-2 s-1). In common with all the most extreme SFXT prototypes (IGR J17544-2619, XTE J1739-302, and IGR J16479-4514), IGR J08408-4503 shows two distinct flare populations. The first one is associated with the brightest outbursts (X-ray luminosity LX ≳ 1035 - 36 erg s-1), while the second comprises dimmer events with typical luminosities of LX ≲ 1035 erg s-1. This double-peaked distribution of the flares as a function of the X-ray luminosity seems to be a ubiquitous feature of the extreme SFXTs. The lower DR of IGR J16328-4726 suggests that this is an intermediate SFXT. IGR J16465-4507 is characterised by a low IDC ~ 5% and a relatively narrow DR ~ 40, reminiscent of classical supergiant

Omega Dante soft x-ray power diagnostic component calibration at the National Synchrotron Light Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campbell, K.M.; Weber, F.A.; Dewald, E.L.

2004-10-01

The Dante soft x-ray spectrometer, installed on the Omega laser facility at the Laboratory for Laser Energetics, University of Rochester, is a 12-channel filter-edge defined soft x-ray power diagnostic. It is used to measure the spectrally resolved, absolute flux from direct drive, indirect drive (hohlraums) and other plasma sources. Dante component calibration efforts using two beam lines, U3C (50 eV-1 keV) and X8A (1-6 keV) at the National Synchrotron Light Source have been implemented to improve the accuracy of these measurements. We have calibrated metallic vacuum x-ray diodes, mirrors and filters.

A versatile soft X-ray transmission system for time resolved in situ microscopy with chemical contrast.

PubMed

Forsberg, J; Englund, C-J; Duda, L-C

2009-08-01

We present the design and operation of a versatile soft X-ray transmission system for time resolved in situ microscopy with chemical contrast. The utility of the setup is demonstrated by results from following a corrosion process of iron in saline environment, subjected to a controlled humid atmosphere. The system includes a transmission flow-cell reactor that allows for in situ microscopic probing with soft X-rays. We employ a full field technique by using a nearly collimated X-ray beam that produces an unmagnified projection of the transmitted soft X-rays (below 1.1 keV) which is magnified and recorded by an optical CCD camera. Time lapse series with chemical contrast allow us to follow and interpret the chemical processes in detail. The obtainable lateral resolution is a few mum, sufficient to detect filiform corrosion on iron.

Comparative study of inelastic squared form factors of the vibronic states of B 1Σu+ , C 1Πu , and E F 1Σg+ for molecular hydrogen: Inelastic x-ray and electron scattering

NASA Astrophysics Data System (ADS)

Xu, Long-Quan; Kang, Xu; Peng, Yi-Geng; Xu, Xin; Liu, Ya-Wei; Wu, Yong; Yang, Ke; Hiraoka, Nozomu; Tsuei, Ku-Ding; Wang, Jian-Guo; Zhu, Lin-Fan

2018-03-01

A joint experimental and theoretical investigation of the valence-shell excitations of hydrogen has been performed by the high-resolution inelastic x-ray scattering and electron scattering as well as the multireference single- and double-excitation configuration-interaction method. Momentum-transfer-dependent inelastic squared form factors for the vibronic series belonging to the B 1Σu+ ,C 1Πu , and E F 1Σg+ electronic states of molecular hydrogen have been derived from the inelastic x-ray scattering method at an impact photon energy around 10 keV, and the electron energy-loss spectra measured at an incident electron energy of 1500 eV. It is found that both the present and the previous calculations cannot satisfactorily reproduce the inelastic squared form-factor profiles for the higher vibronic transitions of the B 1Σu+ state of molecular hydrogen, which may be due to the electronic-vibrational coupling for the higher vibronic states. For the C 1Πu state and some vibronic excitations of E F 1Σg+ state, the present experimental results are in good agreement with the present and previous calculations, while the slight differences between the inelastic x-ray scattering and electron energy-loss spectroscopy results in the larger squared momentum-transfer region may be attributed to the increasing role of the higher-order Born terms in the electron-scattering process.

Hydrodynamic evolution of plasma waveguides for soft-x-ray amplifiers

NASA Astrophysics Data System (ADS)

Oliva, Eduardo; Depresseux, Adrien; Cotelo, Manuel; Lifschitz, Agustín; Tissandier, Fabien; Gautier, Julien; Maynard, Gilles; Velarde, Pedro; Sebban, Stéphane

2018-02-01

High-density, collisionally pumped plasma-based soft-x-ray lasers have recently delivered hundreds of femtosecond pulses, breaking the longstanding barrier of one picosecond. To pump these amplifiers an intense infrared pulse must propagate focused throughout all the length of the amplifier, which spans several Rayleigh lengths. However, strong nonlinear effects hinder the propagation of the laser beam. The use of a plasma waveguide allows us to overcome these drawbacks provided the hydrodynamic processes that dominate the creation and posterior evolution of the waveguide are controlled and optimized. In this paper we present experimental measurements of the radial density profile and transmittance of such waveguide, and we compare them with numerical calculations using hydrodynamic and particle-in-cell codes. Controlling the properties (electron density value and radial gradient) of the waveguide with the help of numerical codes promises the delivery of ultrashort (tens of femtoseconds), coherent soft-x-ray pulses.

SOFT X-RAY IRRADIATION OF SILICATES: IMPLICATIONS FOR DUST EVOLUTION IN PROTOPLANETARY DISKS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ciaravella, A.; Cecchi-Pestellini, C.; Jiménez-Escobar, A.

2016-09-01

The processing of energetic photons on bare silicate grains was simulated experimentally on silicate films submitted to soft X-rays of energies up to 1.25 keV. The silicate material was prepared by means of a microwave assisted sol–gel technique. Its chemical composition reflects the Mg{sub 2}SiO{sub 4} stoichiometry with residual impurities due to the synthesis method. The experiments were performed using the spherical grating monochromator beamline at the National Synchrotron Radiation Research Center in Taiwan. We found that soft X-ray irradiation induces structural changes that can be interpreted as an amorphization of the processed silicate material. The present results may havemore » relevant implications in the evolution of silicate materials in X-ray-irradiated protoplanetary disks.« less

Relations Between FUV Excess and Coronal Soft X-Ray Emission Among Dwarf Stars

NASA Astrophysics Data System (ADS)

Smith, Graeme H.; Hargrave, Mason; Eckholm, Elliot

2017-11-01

The far-ultraviolet magnitudes of late-F, G and early-K dwarfs with (B - V) ⩾ 0.50 as measured by the GALEX satellite are shown to correlate with soft X-ray luminosity. This result indicates that line and continuum emission from stellar active regions make significant contributions to the flux in the GALEX FUV band for late-F, G and K dwarfs. By contrast, detection of a correlation between FUV brightness and soft X-ray luminosity among early-F dwarfs requires subtraction of the photospheric component from the FUV flux. The range in (B - V) among F and G dwarfs over which a correlation between uncorrected FUV magnitude and X-ray luminosity is detected coincides with the range in colour over which coronal and chromospheric emission correlates with stellar rotation.

Generation of bright isolated attosecond soft X-ray pulses driven by multicycle midinfrared lasers

PubMed Central

Chen, Ming-Chang; Mancuso, Christopher; Hernández-García, Carlos; Dollar, Franklin; Galloway, Ben; Popmintchev, Dimitar; Huang, Pei-Chi; Walker, Barry; Plaja, Luis; Jaroń-Becker, Agnieszka A.; Becker, Andreas; Murnane, Margaret M.; Kapteyn, Henry C.; Popmintchev, Tenio

2014-01-01

High harmonic generation driven by femtosecond lasers makes it possible to capture the fastest dynamics in molecules and materials. However, to date the shortest subfemtosecond (attosecond, 10−18 s) pulses have been produced only in the extreme UV region of the spectrum below 100 eV, which limits the range of materials and molecular systems that can be explored. Here we experimentally demonstrate a remarkable convergence of physics: when midinfrared lasers are used to drive high harmonic generation, the conditions for optimal bright, soft X-ray generation naturally coincide with the generation of isolated attosecond pulses. The temporal window over which phase matching occurs shrinks rapidly with increasing driving laser wavelength, to the extent that bright isolated attosecond pulses are the norm for 2-µm driving lasers. Harnessing this realization, we experimentally demonstrate the generation of isolated soft X-ray attosecond pulses at photon energies up to 180 eV for the first time, to our knowledge, with a transform limit of 35 attoseconds (as), and a predicted linear chirp of 300 as. Most surprisingly, advanced theory shows that in contrast with as pulse generation in the extreme UV, long-duration, 10-cycle, driving laser pulses are required to generate isolated soft X-ray bursts efficiently, to mitigate group velocity walk-off between the laser and the X-ray fields that otherwise limit the conversion efficiency. Our work demonstrates a clear and straightforward approach for robustly generating bright isolated attosecond pulses of electromagnetic radiation throughout the soft X-ray region of the spectrum. PMID:24850866

Generation of bright isolated attosecond soft X-ray pulses driven by multicycle midinfrared lasers.

PubMed

Chen, Ming-Chang; Mancuso, Christopher; Hernández-García, Carlos; Dollar, Franklin; Galloway, Ben; Popmintchev, Dimitar; Huang, Pei-Chi; Walker, Barry; Plaja, Luis; Jaroń-Becker, Agnieszka A; Becker, Andreas; Murnane, Margaret M; Kapteyn, Henry C; Popmintchev, Tenio

2014-06-10

High harmonic generation driven by femtosecond lasers makes it possible to capture the fastest dynamics in molecules and materials. However, to date the shortest subfemtosecond (attosecond, 10(-18) s) pulses have been produced only in the extreme UV region of the spectrum below 100 eV, which limits the range of materials and molecular systems that can be explored. Here we experimentally demonstrate a remarkable convergence of physics: when midinfrared lasers are used to drive high harmonic generation, the conditions for optimal bright, soft X-ray generation naturally coincide with the generation of isolated attosecond pulses. The temporal window over which phase matching occurs shrinks rapidly with increasing driving laser wavelength, to the extent that bright isolated attosecond pulses are the norm for 2-µm driving lasers. Harnessing this realization, we experimentally demonstrate the generation of isolated soft X-ray attosecond pulses at photon energies up to 180 eV for the first time, to our knowledge, with a transform limit of 35 attoseconds (as), and a predicted linear chirp of 300 as. Most surprisingly, advanced theory shows that in contrast with as pulse generation in the extreme UV, long-duration, 10-cycle, driving laser pulses are required to generate isolated soft X-ray bursts efficiently, to mitigate group velocity walk-off between the laser and the X-ray fields that otherwise limit the conversion efficiency. Our work demonstrates a clear and straightforward approach for robustly generating bright isolated attosecond pulses of electromagnetic radiation throughout the soft X-ray region of the spectrum.

Soft X-ray spectromicroscopy for speciation, quantitation and nano-eco-toxicology of nanomaterials.

PubMed

Lawrence, J R; Swerhone, G D W; Dynes, J J; Korber, D R; Hitchcock, A P

2016-02-01

There is a critical need for methods that provide simultaneous detection, identification, quantitation and visualization of nanomaterials at their interface with biological and environmental systems. The approach should allow speciation as well as elemental analysis. Using the intrinsic X-ray absorption properties, soft X-ray scanning transmission X-ray spectromicroscopy (STXM) allows characterization and imaging of a broad range of nanomaterials, including metals, oxides and organic materials, and at the same time is able to provide detailed mapping of biological components. Thus, STXM offers considerable potential for application to research on nanomaterials in biology and the environment. The potential and limitations of STXM in this context are discussed using a range of examples, focusing on the interaction of nanomaterials with microbial cells, biofilms and extracellular polymers. The studies outlined include speciation and mapping of metal-containing nanomaterials (Ti, Ni, Cu) and carbon-based nanomaterials (multiwalled carbon nanotubes, C60 fullerene). The benefits of X-ray fluorescence detection in soft X-ray STXM are illustrated with a study of low levels of Ni in a natural river biofilm. © 2014 The Authors Journal of Microscopy © 2014 Royal Microscopical Society.

Boundary displacement measurements using multi-energy soft x-rays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tritz, K., E-mail: ktritz@pppl.gov; Stutman, D.; Diallo, A.

The Multi-Energy Soft X-ray (ME-SXR) system on NSTX provides radial profiles of soft X-ray emission, measured through a set of filters with varying thickness, which have been used to reconstruct the electron temperature on fast time scales (∼10 kHz). In addition to this functionality, here we show that the ME-SXR system can be used to measure the boundary displacement of the NSTX plasma with a few mm spatial resolution during magnetohydrodyamic (MHD) activity. Boundary displacement measurements can serve to inform theoretical predictions of neoclassical toroidal viscosity, and will be used to investigate other edge phenomena on NSTX-U. For example, boundary measurementsmore » using filtered SXR measurements can provide information on pedestal steepness and dynamic evolution leading up to and during edge localized modes (ELMs). Future applications include an assessment of a simplified, filtered SXR edge detection system as well as its suitability for real-time non-magnetic boundary feedback for ELMs, MHD, and equilibrium position control.« less

In-flight calibration of Hitomi Soft X-ray Spectrometer. (1) Background

NASA Astrophysics Data System (ADS)

Kilbourne, Caroline A.; Sawada, Makoto; Tsujimoto, Masahiro; Angellini, Lorella; Boyce, Kevin R.; Eckart, Megan E.; Fujimoto, Ryuichi; Ishisaki, Yoshitaka; Kelley, Richard L.; Koyama, Shu; Leutenegger, Maurice A.; Loewenstein, Michael; McCammon, Dan; Mitsuda, Kazuhisa; Nakashima, Shinya; Porter, Frederick S.; Seta, Hiromi; Takei, Yoh; Tashiro, Makoto S.; Terada, Yukikatsu; Yamada, Shinya; Yamasaki, Noriko Y.

2018-03-01

The X-Ray Spectrometer (XRS) instrument of Suzaku provided the first measurement of the non-X-ray background (NXB) of an X-ray calorimeter spectrometer, but the data set was limited. The Soft X-ray Spectrometer (SXS) instrument of Hitomi was able to provide a more detailed picture of X-ray calorimeter background, with more than 360 ks of data while pointed at the Earth, and a comparable amount of blank-sky data. These data are important not only for analyzing SXS science data, but also for categorizing the contributions to the NXB in X-ray calorimeters as a class. In this paper, we present the contributions to the SXS NXB, the types and effectiveness of the screening, the interaction of the screening with the broad-band redistribution, and the residual background spectrum as a function of magnetic cut-off rigidity. The orbit-averaged SXS NXB in the range 0.3-12 keV was 4 × 10-2 counts s-1 cm-2. This very low background in combination with groundbreaking spectral resolution gave SXS unprecedented sensitivity to weak spectral lines.

THE BLAZAR EMISSION ENVIRONMENT: INSIGHT FROM SOFT X-RAY ABSORPTION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Furniss, A.; Williams, D. A.; Fumagalli, M.

Collecting experimental insight into the relativistic particle populations and emission mechanisms at work within TeV-emitting blazar jets, which are spatially unresolvable in most bands and have strong beaming factors, is a daunting task. New observational information has the potential to lead to major strides in understanding the acceleration site parameters. Detection of molecular carbon monoxide (CO) in TeV emitting blazars, however, implies the existence of intrinsic gas, a connection often found in photo-dissociated region models and numerical simulations. The existence of intrinsic gas within a blazar could provide a target photon field for Compton up-scattering of photons to TeV energiesmore » by relativistic particles. We investigate the possible existence of intrinsic gas within the three TeV emitting blazars RGB J0710+591, W Comae, and 1ES 1959+650 which have measurements or upper limits on molecular CO line luminosity using an independent technique that is based on the spectral analysis of soft X-rays. Evidence for X-ray absorption by additional gas beyond that measured within the Milky Way is searched for in Swift X-ray Telescope (XRT) data between 0.3 and 10 keV. Without complementary information from another measurement, additional absorption could be misinterpreted as an intrinsically curved X-ray spectrum since both models can frequently fit the soft X-ray data. After breaking this degeneracy, we do not find evidence for intrinsically curved spectra for any of the three blazars. Moreover, no evidence for intrinsic gas is evident for RGB J0710+591 and W Comae, while the 1ES 1959+650 XRT data support the existence of intrinsic gas with a column density of {approx}1 Multiplication-Sign 10{sup 21} cm{sup -2}.« less

Distinct charge dynamics in battery electrodes revealed by in situ and operando soft X-ray spectroscopy

PubMed Central

Liu, Xiaosong; Wang, Dongdong; Liu, Gao; Srinivasan, Venkat; Liu, Zhi; Hussain, Zahid; Yang, Wanli

2013-01-01

Developing high-performance batteries relies on material breakthroughs. During the past few years, various in situ characterization tools have been developed and have become indispensible in studying and the eventual optimization of battery materials. However, soft X-ray spectroscopy, one of the most sensitive probes of electronic states, has been mainly limited to ex situ experiments for battery research. Here we achieve in situ and operando soft X-ray absorption spectroscopy of lithium-ion battery cathodes. Taking advantage of the elemental, chemical and surface sensitivities of soft X-rays, we discover distinct lithium-ion and electron dynamics in Li(Co1/3Ni1/3Mn1/3)O2 and LiFePO4 cathodes in polymer electrolytes. The contrast between the two systems and the relaxation effect in LiFePO4 is attributed to a phase transformation mechanism, and the mesoscale morphology and charge conductivity of the electrodes. These discoveries demonstrate feasibility and power of in situ soft X-ray spectroscopy for studying integrated and dynamic effects in batteries. PMID:24100759

Soft X-ray imaging of thick carbon-based materials using the normal incidence multilayer optics.

PubMed

Artyukov, I A; Feschenko, R M; Vinogradov, A V; Bugayev, Ye A; Devizenko, O Y; Kondratenko, V V; Kasyanov, Yu S; Hatano, T; Yamamoto, M; Saveliev, S V

2010-10-01

The high transparency of carbon-containing materials in the spectral region of "carbon window" (lambda approximately 4.5-5nm) introduces new opportunities for various soft X-ray microscopy applications. The development of efficient multilayer coated X-ray optics operating at the wavelengths of about 4.5nm has stimulated a series of our imaging experiments to study thick biological and synthetic objects. Our experimental set-up consisted of a laser plasma X-ray source generated with the 2nd harmonics of Nd-glass laser, scandium-based thin-film filters, Co/C multilayer mirror and X-ray film UF-4. All soft X-ray images were produced with a single nanosecond exposure and demonstrated appropriate absorption contrast and detector-limited spatial resolution. A special attention was paid to the 3D imaging of thick low-density foam materials to be used in design of laser fusion targets.

Laboratory experiments on soft x-ray emissions from the solar wind

NASA Astrophysics Data System (ADS)

Kanda, T.; Ohashi, H.; Maeno, S.; Ishida, T.; Tanuma, H.; Akamatsu, H.; Abe, Y.; Yokota, W.; Henmi, K.; Ishisaki, Y.; Ezoe, Y.; Ohashi, T.; Shinozaki, K.; Mitsuda, K.

2011-06-01

We have observed emission spectra in collisions of hydrogen-like oxygen and nitrogen ions with a helium target gas in the soft x-ray region using a window-less Si(Li) detector at collision energies of about 100 keV. The dominant soft x-ray emission is the 1s2-1s2p transition of helium-like ions produced by a single-electron capture reaction. We indicate that the cascades from the upper states give a large population of the 2p state, even though direct capture into the 2p state is much smaller than the 3ell and 4ell states. The intensity ratios of the 1s-2p and 1s-3p transitions are discussed, along with a comparison with the theoretical calculation.

OSO-8 soft X-ray wheel experiment: Data analysis

NASA Technical Reports Server (NTRS)

Kraushaar, W. L.

1982-01-01

The soft X-ray experiment hardware and its operation are described. The device included six X-ray proportional counters, two of which, numbers 1 and 4, were pressurized with on-board methane gas supplies. Number 4 developed an excessive leak rate early in the mission and was turned off on 1975 day number 282 except for brief (typically 2-hour) periods up to day 585 after which it as left off. Counter 1 worked satisfactorily until 1975 day number 1095 (January 1, 1978) at which time the on-board methane supply was depleted. The other four counters were sealed and all except number 3 worked satisfactorily throughout the mission which terminated with permanent satellie shut-down on day 1369. This was the first large area thin-window, gas-flow X-ray detector to be flown in orbit. The background problems were severe and consumed a very large portion of the data analysis effort. These background problems were associated with the Earth's trapped electron belts.

Spatial power-spectra from Yohkoh soft X-ray images

NASA Technical Reports Server (NTRS)

Martens, Petrus C. H.; Gomez, Daniel O.

1992-01-01

We analyze three sequences of images from active regions, and a full disk image obtained by Yohkoh's Soft X-ray Telescope. Two sequences are from a region at center disk observed through different filters, and one sequence is from the limb. After Fourier-transforming the X-ray intensity of the images we find nearly isotropic power-spectra with an azimuthally integrated slope of -2.1 for the center disk, and -2.8 for the limb images. The full-disk picture yields a spectrum of -2.4. These results are different from the active region spectra obtained with the Normal Incidence X-ray Telescope which have a slope of the order of -3.0, and we ascribe this to the difference in temperature response between the instruments. However, both the SXT and NIXT results are consistent with coronal heating as the end result of a downward quasistatic cascade (in lengthscales) of free magnetic energy in the corona, driven by footpoint motions in the photosphere.

Near-edge x-ray absorption fine structure spectroscopy at atmospheric pressure with a table-top laser-induced soft x-ray source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kühl, Frank-Christian, E-mail: Frank-christian.kuehl@mail.de; Müller, Matthias, E-mail: matthias.mueller@llg-ev.de; Schellhorn, Meike

2016-07-15

The authors present a table-top soft x-ray absorption spectrometer, accomplishing investigations of the near-edge x-ray absorption fine structure (NEXAFS) in a laboratory environment. The system is based on a low debris plasma ignited by a picosecond laser in a pulsed krypton gas jet, emitting soft x-ray radiation in the range from 1 to 5 nm. For absorption spectroscopy in and around the “water window” (2.3–4.4 nm), a compact helium purged sample compartment for experiments at atmospheric pressure has been constructed and tested. NEXAFS measurements on CaCl{sub 2} and KMnO{sub 4} samples were conducted at the calcium and manganese L-edges, as well asmore » at the oxygen K-edge in air, atmospheric helium, and under vacuum, respectively. The results indicate the importance of atmospheric conditions for an investigation of sample hydration processes.« less

Heterodyne x-ray diffuse scattering from coherent phonons

DOE PAGES

Kozina, M.; Trigo, M.; Chollet, M.; ...

2017-08-10

Here in this paper, we report Fourier-transform inelastic x-ray scattering measurements of photoexcited GaAs with embedded ErAs nanoparticles. We observe temporal oscillations in the x-ray scattering intensity, which we attribute to inelastic scattering from coherent acoustic phonons. Unlike in thermal equilibrium, where inelastic x-ray scattering is proportional to the phonon occupation, we show that the scattering is proportional to the phonon amplitude for coherent states. The wavevectors of the observed phonons extend beyond the excitation wavevector. The nanoparticles break the discrete translational symmetry of the lattice, enabling the generation of large wavevector coherent phonons. Elastic scattering of x-ray photons frommore » the nanoparticles provides a reference for heterodyne mixing, yielding signals proportional to the phonon amplitude.« less

Magnetoelectric confinement and stabilization of Z pinch in a soft-x-ray Ar(+8) laser.

PubMed

Szasz, J; Kiss, M; Santa, I; Szatmari, S; Kukhlevsky, S V

2013-05-03

Magnetoelectric confinement and stabilization of the plasma column in a soft-x-ray Ar(+8) laser, which is excited by a capillary Z pinch, via the combined magnetic and electric fields of the gliding surface discharge is experimentally demonstrated. Unlike soft-x-ray lasers excited by the conventional capillary Z pinches, the magnetoelectric confinement and stabilization of plasma do provide the laser operation without using any external preionization circuit.

3D nanoscale imaging of biological samples with laboratory-based soft X-ray sources

NASA Astrophysics Data System (ADS)

Dehlinger, Aurélie; Blechschmidt, Anne; Grötzsch, Daniel; Jung, Robert; Kanngießer, Birgit; Seim, Christian; Stiel, Holger

2015-09-01

In microscopy, where the theoretical resolution limit depends on the wavelength of the probing light, radiation in the soft X-ray regime can be used to analyze samples that cannot be resolved with visible light microscopes. In the case of soft X-ray microscopy in the water-window, the energy range of the radiation lies between the absorption edges of carbon (at 284 eV, 4.36 nm) and oxygen (543 eV, 2.34 nm). As a result, carbon-based structures, such as biological samples, posses a strong absorption, whereas e.g. water is more transparent to this radiation. Microscopy in the water-window, therefore, allows the structural investigation of aqueous samples with resolutions of a few tens of nanometers and a penetration depth of up to 10μm. The development of highly brilliant laser-produced plasma-sources has enabled the transfer of Xray microscopy, that was formerly bound to synchrotron sources, to the laboratory, which opens the access of this method to a broader scientific community. The Laboratory Transmission X-ray Microscope at the Berlin Laboratory for innovative X-ray technologies (BLiX) runs with a laser produced nitrogen plasma that emits radiation in the soft X-ray regime. The mentioned high penetration depth can be exploited to analyze biological samples in their natural state and with several projection angles. The obtained tomogram is the key to a more precise and global analysis of samples originating from various fields of life science.

The detection of soft X-rays with charged coupled detectors

NASA Technical Reports Server (NTRS)

Burstein, P.; Davis, John M.

1989-01-01

The characteristics of an ideal soft X-ray imaging detector are enumerated. Of recent technical developments the CCD or charge coupled device goes furthest to meeting these requirements. Several properties of CCDs are described with reference to experimental work and their application to practical instruments is reviewed.

Compact "diode-based" multi-energy soft x-ray diagnostic for NSTX.

PubMed

Tritz, K; Clayton, D J; Stutman, D; Finkenthal, M

2012-10-01

A novel and compact, diode-based, multi-energy soft x-ray (ME-SXR) diagnostic has been developed for the National Spherical Tokamak Experiment. The new edge ME-SXR system tested on NSTX consists of a set of vertically stacked diode arrays, each viewing the plasma tangentially through independent pinholes and filters providing an overlapping view of the plasma midplane which allows simultaneous SXR measurements with coarse sub-sampling of the x-ray spectrum. Using computed x-ray spectral emission data, combinations of filters can provide fast (>10 kHz) measurements of changes in the electron temperature and density profiles providing a method to "fill-in" the gaps of the multi-point Thomson scattering system.

Soft X-ray Focusing Telescope Aboard AstroSat: Design, Characteristics and Performance

NASA Astrophysics Data System (ADS)

Singh, K. P.; Stewart, G. C.; Westergaard, N. J.; Bhattacharayya, S.; Chandra, S.; Chitnis, V. R.; Dewangan, G. C.; Kothare, A. T.; Mirza, I. M.; Mukerjee, K.; Navalkar, V.; Shah, H.; Abbey, A. F.; Beardmore, A. P.; Kotak, S.; Kamble, N.; Vishwakarama, S.; Pathare, D. P.; Risbud, V. M.; Koyande, J. P.; Stevenson, T.; Bicknell, C.; Crawford, T.; Hansford, G.; Peters, G.; Sykes, J.; Agarwal, P.; Sebastian, M.; Rajarajan, A.; Nagesh, G.; Narendra, S.; Ramesh, M.; Rai, R.; Navalgund, K. H.; Sarma, K. S.; Pandiyan, R.; Subbarao, K.; Gupta, T.; Thakkar, N.; Singh, A. K.; Bajpai, A.

2017-06-01

The Soft X-ray focusing Telescope (SXT), India's first X-ray telescope based on the principle of grazing incidence, was launched aboard the AstroSat and made operational on October 26, 2015. X-rays in the energy band of 0.3-8.0 keV are focussed on to a cooled charge coupled device thus providing medium resolution X-ray spectroscopy of cosmic X-ray sources of various types. It is the most sensitive X-ray instrument aboard the AstroSat. In its first year of operation, SXT has been used to observe objects ranging from active stars, compact binaries, supernova remnants, active galactic nuclei and clusters of galaxies in order to study its performance and quantify its characteriztics. Here, we present an overview of its design, mechanical hardware, electronics, data modes, observational constraints, pipeline processing and its in-orbit performance based on preliminary results from its characterization during the performance verification phase.

LCLS in—photon out: fluorescence measurement of neon using soft x-rays

DOE PAGES

Obaid, Razib; Buth, Christian; Dakovski, Georgi L.; ...

2018-01-09

Here, we measured the fluorescence photon yield of neon upon soft x-ray ionization (~1200 eV) from the x-ray free-electron laser at Linac Coherent Light Source, and demonstrated the usage of a grazing incidence spectrometer with a variable line spacing grating to perform x-ray fluorescence spectroscopy on a gas phase system. Our measurements also allowed us to estimate the focal size of the beam from the theoretical description developed, in terms of the rate equation approximation accounting for photoionization shake off of neutral neon and double auger decay of single core holes.

LCLS in—photon out: fluorescence measurement of neon using soft x-rays

NASA Astrophysics Data System (ADS)

Obaid, Razib; Buth, Christian; Dakovski, Georgi L.; Beerwerth, Randolf; Holmes, Michael; Aldrich, Jeff; Lin, Ming-Fu; Minitti, Michael; Osipov, Timur; Schlotter, William; Cederbaum, Lorenz S.; Fritzsche, Stephan; Berrah, Nora

2018-02-01

We measured the fluorescence photon yield of neon upon soft x-ray ionization (∼1200 eV) from the x-ray free-electron laser at Linac Coherent Light Source, and demonstrated the usage of a grazing incidence spectrometer with a variable line spacing grating to perform x-ray fluorescence spectroscopy on a gas phase system. Our measurements also allowed us to estimate the focal size of the beam from the theoretical description developed, in terms of the rate equation approximation accounting for photoionization shake off of neutral neon and double auger decay of single core holes.

X-ray echo spectroscopy (Conference Presentation)

NASA Astrophysics Data System (ADS)

Shvyd'ko, Yuri V.

2016-09-01

X-ray echo spectroscopy, a counterpart of neutron spin-echo, was recently introduced [1] to overcome limitations in spectral resolution and weak signals of the traditional inelastic x-ray scattering (IXS) probes. An image of a point-like x-ray source is defocused by a dispersing system comprised of asymmetrically cut specially arranged Bragg diffracting crystals. The defocused image is refocused into a point (echo) in a time-reversal dispersing system. If the defocused beam is inelastically scattered from a sample, the echo signal acquires a spatial distribution, which is a map of the inelastic scattering spectrum. The spectral resolution of the echo spectroscopy does not rely on the monochromaticity of the x-rays, ensuring strong signals along with a very high spectral resolution. Particular schemes of x-ray echo spectrometers for 0.1-meV and 0.02-meV ultra-high-resolution IXS applications (resolving power > 10^8) with broadband 5-13 meV dispersing systems will be presented featuring more than 1000-fold signal enhancement. The technique is general, applicable in different photon frequency domains. [1.] Yu. Shvyd'ko, Phys. Rev. Lett. 116, accepted (2016), arXiv:1511.01526.

Optical Design and Performance of the Taiwan Inelastic X-Ray Scattering Beamline (BL12XU) at SPring-8

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cai, Y.Q.; Chow, P.; Chen, C.C.

2004-05-12

As part of the Taiwan x-ray facility at SPring-8, we have designed, constructed and commissioned a dedicated Inelastic X-ray Scattering (IXS) beamline (BL12XU) for both resonant and non-resonant experiments on electronic excitations in correlated electron systems with energy resolution from 10-1000 meV. At the Si(555) near-backscattering energy of 9.886 keV, a total energy resolution of 70 meV has been achieved with flux of 1.5x1011 phs/sec/50meV. The optical design and performance of the beamline are presented and discussed with selected results from recent commissioning experiments.

Effect of Pressure on Valence and Structural Properties of YbFe 2 Ge 2 Heavy Fermion Compound—A Combined Inelastic X-ray Spectroscopy, X-ray Diffraction, and Theoretical Investigation

DOE PAGES

Kumar, Ravhi S.; Svane, Axel; Vaitheeswaran, Ganapathy; ...

2015-10-19

We measured the crystal structure and the Yb valence of the YbFe 2Ge 2 heavy fermion compound at room temperature and under high pressures using high-pressure powder X-ray diffraction and X-ray absorption spectroscopy via both partial fluorescence yield and resonant inelastic X-ray emission techniques. Moreover, the measurements are complemented by first-principles density functional theoretical calculations using the self-interaction corrected local spin density approximation investigating in particular the magnetic structure and the Yb valence. Finally, while the ThCr 2Si 2-type tetragonal (I4/mmm) structure is stable up to 53 GPa, the X-ray emission results show an increase of the Yb valence frommore » v = 2.72(2) at ambient pressure to v = 2.93(3) at ~9 GPa, where at low temperature a pressure-induced quantum critical state was reported.« less

X-ray magnetic circular dichroism measured at the Fe K-edge with a reduced intrinsic broadening: x-ray absorption spectroscopy versus resonant inelastic x-ray scattering measurements

NASA Astrophysics Data System (ADS)

Juhin, Amélie; Sainctavit, Philippe; Ollefs, Katharina; Sikora, Marcin; Filipponi, Adriano; Glatzel, Pieter; Wilhelm, Fabrice; Rogalev, Andrei

2016-12-01

X-ray magnetic circular dichroism is measured at the Fe K pre-edge in yttrium iron garnet using two different procedures that allow reducing the intrinsic broadening due to the 1s corehole lifetime. First, deconvolution of XMCD data measured in total fluorescence yield (TFY) with an extremely high signal-to-noise ratio enables a factor of 2.4 to be gained in the XMCD intensity. Ligand field multiplet calculations performed with different values of intrinsic broadening show that deconvolving such high quality XMCD data is similar to reducing the lifetime broadening from a 1s corehole to a 2p corehole. Second, MCD is measured by resonant inelastic x-ray scattering spectroscopy as a function of incident energy and emission energy. Selection of a fixed emission energy, instead of using the TFY, allows enhancing the MCD intensity up to a factor of  ˜4.7. However, this significantly changes the spectral shape of the XMCD signal, which cannot be interpreted any more as an absorption spectrum.

Soft X-Ray Absorption Spectroscopy of High-Abrasion-Furnace Carbon Black

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muramatsu, Yasuji; Harada, Ryusuke; Gullikson, Eric M.

2007-02-02

The soft x-ray absorption spectra of high-abrasion-furnace carbon black were measured to obtain local-structure/chemical-states information of the primary particles and/or crystallites. The soft x-ray absorption spectral features of carbon black represent broader {pi}* and {sigma}* peak structures compared to highly oriented pyrolytic graphite (HOPG). The subtracted spectra between the carbon black and HOPG, (carbon black) - (HOPG), show double-peak structures on both sides of the {pi}* peak. The lower-energy peak, denoted as the 'pre-peak', in the subtracted spectra and the {pi}*/{sigma}* peak intensity ratio in the absorption spectra clearly depend on the specific surface area by nitrogen adsorption (NSA). Therefore,more » it is concluded that the pre-peak intensity and the {pi}*/{sigma}* ratio reflect the local graphitic structure of carbon black.« less

Soft x-ray power diagnostic improvements at the Omega Laser Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sorce, C.; Schein, J.; Weber, F.

2006-10-15

Soft x-ray power diagnostics are essential for evaluating high temperature laser plasma experiments. The Dante soft x-ray spectrometer, a core diagnostic for radiation flux and temperature measurements of Hohlraums, installed on the Omega Laser Facility at the Laboratory for Laser Energetics has recently undergone a series of upgrades. Work performed at Brookhaven National Laboratory for the development of the National Ignition Facility (NIF) Dante spectrometer enables the Omega Dante to offer a total of 18 absolutely calibrated channels in the energy range from 50 eV to 20 keV. This feature provides Dante with the capability to measure higher, NIF relevant,more » radiation temperatures with increased accuracy including a differentiation of higher energy radiation such as the Au M and L bands. Diagnostic monitoring using experimental data from directly driven Au spherical shots is discussed.« less

Weak soft X-ray excesses need not result from the high-frequency tail of the optical/ultraviolet bump in active galactic nuclei

NASA Technical Reports Server (NTRS)

Czerny, Bozena; Zycki, Piotr T.

1994-01-01

The broad-band ROSAT/EXOSAT X-ray spectra of six Seyfert 1 galaxies are fitted by a model consisting of a direct power law and a component due to reflection/reprocessing from a partially ionized, optically thick medium. The reflected spectrum contains emission features from various elements in the soft X-ray range. In all objects but one (Mrk 335), the fit is satisfactory, and no additional soft X-ray excess is required by the data. This means that in most sources there is no need for the thermal 'big blue bumps' to extend into soft X-rays, and the soft X-ray excesses reported previously can be explained by reflection/reprocessing. Satisfactory fits are obtained for a medium ionized by a source radiating at less than or approximately 15% of the Eddington rate. The fits require that the reflection is enhanced relative to an isotropically emitting source above a flat disk. The necessary high effectiveness of reflection in the soft X-ray band requires strong soft thermal flux dominating over hard X-rays.

Resonant inelastic X-ray scattering on synthetic nickel compounds and Ni-Fe hydrogenase protein

NASA Astrophysics Data System (ADS)

Sanganas, Oliver; Löscher, Simone; Pfirrmann, Stefan; Marinos, Nicolas; Glatzel, Pieter; Weng, Tsu-Chien; Limberg, Christian; Driess, Matthias; Dau, Holger; Haumann, Michael

2009-11-01

Ni-Fe hydrogenases are proteins catalyzing the oxidative cleavage of dihydrogen (H2) and proton reduction to H2 at high turnover rates. Their active site is a heterobimetallic center comprising one Ni and one Fe atom. To understand the function of the site, well resolved structural and electronic information is required. Such information is expected to become accessible by high resolution X-ray absorption and emission techniques, which are rapidly developing at third generation synchrotron radiation sources. We studied a number of synthetic Ni compounds, which mimic relevant features of the Ni site in hydrogenases, and the Ni site in the soluble, NAD-reducing hydrogenase (SH) from the bacterium Ralstonia eutropha by resonant inelastic X-ray scattering (RIXS) using a Rowland-type spectrometer at the ESRF. The SH is particularly interesting because its H2-cleavage reaction is highly resistant against inhibition by O2. Kα-fluorescence detected RIXS planes in the 1s→3d region of the X-ray absorption spectrum were recorded on the protein which allow to extract L3-edge type spectra Spectral features of the protein are compared to those of the model compounds.

A reaction cell for ambient pressure soft x-ray absorption spectroscopy

NASA Astrophysics Data System (ADS)

Castán-Guerrero, C.; Krizmancic, D.; Bonanni, V.; Edla, R.; Deluisa, A.; Salvador, F.; Rossi, G.; Panaccione, G.; Torelli, P.

2018-05-01

We present a new experimental setup for performing X-ray Absorption Spectroscopy (XAS) in the soft X-ray range at ambient pressure. The ambient pressure XAS setup is fully compatible with the ultra high vacuum environment of a synchrotron radiation spectroscopy beamline end station by means of ultrathin Si3N4 membranes acting as windows for the X-ray beam and seal of the atmospheric sample environment. The XAS detection is performed in total electron yield (TEY) mode by probing the drain current from the sample with a picoammeter. The high signal/noise ratio achievable in the TEY mode, combined with a continuous scanning of the X-ray energies, makes it possible recording XAS spectra in a few seconds. The first results show the performance of this setup to record fast XAS spectra from sample surfaces exposed at atmospheric pressure, even in the case of highly insulating samples. The use of a permanent magnet inside the reaction cell enables the measurement of X-ray magnetic circular dichroism at ambient pressure.

A search for a cosmological component of the soft X-ray background in the direction of M31

NASA Technical Reports Server (NTRS)

Margon, B.; Bowyer, S.; Cruddace, R.; Heiles, C.; Lampton, M.; Troland, T.

1974-01-01

Results of an experiment to search for absorption of the soft diffuse X-ray background by M31, the Andromeda Nebula, are presented. Both X-ray and 21-cm observations were obtained with high spatial resolution; the X-ray detector had a 2-degree field of view, and the 21-cm data were taken with 20-minute resolution. The results establish that at least 48 percent of the soft X-ray flux has a local source, but that the remainder may be of distant origin and therefore of cosmological significance.

Experiment and application of soft x-ray grazing incidence optical scattering phenomena

NASA Astrophysics Data System (ADS)

Chen, Shuyan; Li, Cheng; Zhang, Yang; Su, Liping; Geng, Tao; Li, Kun

2017-08-01

For short wavelength imaging systems，surface scattering effects is one of important factors degrading imaging performance. Study of non-intuitive surface scatter effects resulting from practical optical fabrication tolerances is a necessary work for optical performance evaluation of high resolution short wavelength imaging systems. In this paper, Soft X-ray optical scattering distribution is measured by a soft X-ray reflectometer installed by my lab, for different sample mirrors、wavelength and grazing angle. Then aim at space solar telescope, combining these scattered light distributions, and surface scattering numerical model of grazing incidence imaging system, PSF and encircled energy of optical system of space solar telescope are computed. We can conclude that surface scattering severely degrade imaging performance of grazing incidence systems through analysis and computation.

Characterizing automotive fuel cell materials by soft x-ray scanning transmission x-ray microscopy

NASA Astrophysics Data System (ADS)

Hitchcock, A. P.; Lee, V.; Wu, J.; West, M. M.; Cooper, G.; Berejnov, V.; Soboleva, T.; Susac, D.; Stumper, J.

2016-01-01

Proton-Exchange Membrane Fuel Cell (PEM-FC) based engines are being developed rapidly for near-term implementation in hydrogen fueled, mass production, personal automobiles. Research is focused on understanding and controlling various degradation processes (carbon corrosion, Pt migration, cold start), and reducing cost by reducing or eliminating Pt catalyst. We are using soft X-ray scanning transmission X-ray microscopy (STXM) at the S 2p, C 1s, O 1s and F 1s edges to study a variety of issues related to optimization of PEM-FC materials for automotive applications. A method to efficiently and accurately measure perfluorosulfonic acid distributions was developed and is being used to better understand how different loadings and preparation methods affect the ionomer distribution in the cathode. Progress towards an environmental cell capable of controlling the temperature and humidity of a PEM-FC sample in the STXM is described. Methods for studying the 3D chemical structure of PEM-FC are outlined.

Characterizing automotive fuel cell materials by soft x-ray scanning transmission x-ray microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hitchcock, A. P., E-mail: aph@mcmaster.ca; Lee, V.; Wu, J.

Proton-Exchange Membrane Fuel Cell (PEM-FC) based engines are being developed rapidly for near-term implementation in hydrogen fueled, mass production, personal automobiles. Research is focused on understanding and controlling various degradation processes (carbon corrosion, Pt migration, cold start), and reducing cost by reducing or eliminating Pt catalyst. We are using soft X-ray scanning transmission X-ray microscopy (STXM) at the S 2p, C 1s, O 1s and F 1s edges to study a variety of issues related to optimization of PEM-FC materials for automotive applications. A method to efficiently and accurately measure perfluorosulfonic acid distributions was developed and is being used tomore » better understand how different loadings and preparation methods affect the ionomer distribution in the cathode. Progress towards an environmental cell capable of controlling the temperature and humidity of a PEM-FC sample in the STXM is described. Methods for studying the 3D chemical structure of PEM-FC are outlined.« less

First Peek of ASTRO-H Soft X-Ray Telescope (SXT) In-Orbit Performance

NASA Technical Reports Server (NTRS)

Okajima, Takashi; Soong, Yang; Serlemitsos, Peter J.; Mori, Hideyuki; Olsen, Lawrence; Robinson, David; Koenecke, Richard; Chang, William; Hahne, David; Iisuka, Ryo;

Elemental mercury oxidation in an electrostatic precipitator enhanced with in situ soft X-ray irradiation.

PubMed

Jing, He; Wang, Xiaofei; Wang, Wei-Ning; Biswas, Pratim

2015-04-01

Corona discharge based techniques are promising approaches for oxidizing elemental mercury (Hg0) in flue gas from coal combustion. In this study, in-situ soft X-rays were coupled to a DC (direct current) corona-based electrostatic precipitator (ESP). The soft X-rays significantly enhanced Hg0 oxidation, due to generation of electrons from photoionization of gas molecules and the ESP electrodes. This coupling technique worked better in the positive corona discharge mode because more electrons were in the high energy region near the electrode. Detailed mechanisms of Hg0 oxidation are proposed and discussed based on ozone generation measurements and Hg0 oxidation behavior observations in single gas environments (O2, N2, and CO2). The effect of O2 concentration in flue gas, as well as the effects of particles (SiO2, TiO2, and KI) was also evaluated. In addition, the performance of a soft X-rays coupled ESP in Hg0 oxidations was investigated in a lab-scale coal combustion system. With the ESP voltage at +10 kV, soft X-ray enhancement, and KI addition, mercury oxidation was maximized. Mercury is a significant-impact atmospheric pollutant due to its toxicity. Coal-fired power plants are the primary emission sources of anthropogenic releases of mercury; hence, mercury emission control from coal-fired power plant is important. This study provides an alternative mercury control technology for coal-fired power plants. The proposed electrostatic precipitator with in situ soft X-rays has high efficiency on elemental mercury conversion. Effects of flue gas conditions (gas compositions, particles, etc.) on performance of this technology were also evaluated, which provided guidance on the application of the technology for coal-fired power plant mercury control.

X-ray laser microscope apparatus

DOEpatents

Suckewer, Szymon; DiCicco, Darrell S.; Hirschberg, Joseph G.; Meixler, Lewis D.; Sathre, Robert; Skinner, Charles H.

1990-01-01

A microscope consisting of an x-ray contact microscope and an optical microscope. The optical, phase contrast, microscope is used to align a target with respect to a source of soft x-rays. The source of soft x-rays preferably comprises an x-ray laser but could comprise a synchrotron or other pulse source of x-rays. Transparent resist material is used to support the target. The optical microscope is located on the opposite side of the transparent resist material from the target and is employed to align the target with respect to the anticipated soft x-ray laser beam. After alignment with the use of the optical microscope, the target is exposed to the soft x-ray laser beam. The x-ray sensitive transparent resist material whose chemical bonds are altered by the x-ray beam passing through the target mater GOVERNMENT LICENSE RIGHTS This invention was made with government support under Contract No. De-FG02-86ER13609 awarded by the Department of Energy. The Government has certain rights in this invention.

The soft x-ray properties of a complete sample of optically selected quasars. 1: First results

NASA Technical Reports Server (NTRS)

Laor, Ari; Fiore, Fabrizio; Elvis, Martin; Wilkes, Belinda J.; Mcdowell, Jonathan C.

1994-01-01

We present the results of ROSAT position sensitive proportional counter (PSPC) observations of 10 quasars. These objects are part of our ROSAT program to observe a complete sample of optically selected quasars. This sample includes all 23 quasars from the bright quasar survey with a redshift z less than or = 0.400 and a Galactic H I column density N(sup Gal sub H I) less than 1.9 x 10(exp 20)/sq cm. These selection criteria, combined with the high sensitivity and improved energy resolution of the PSPC, allow us to determine the soft (approximately 0.2-2 keV) X-ray spectra of quasars with about an order of magnitude higher precision compared with earlier soft X-ray observations. The following main results are obtained: Strong correlations are suggested between the soft X-ray spectral slope alpha(sub x) and the following emission line parameters: H beta Full Width at Half Maximum (FWHM), L(sub O III), and the Fe II/H beta flux ratio. These correlations imply the following: (1) The quasar's environment is likely to be optically thin down to approximately 0.2 keV. (2) In most objects alpha(sub x) varies by less than approximately 10% on timescales shorter than a few years. (3) alpha(sub x) might be a useful absolute luminosity indicator in quasars. (4) The Galactic He I and H I column densities are well correlated. Most spectra are well characterized by a simple power law, with no evidence for either significant absorption excess or emission excess at low energies, to within approximately 30%. We find mean value of alpha(sub x) = -1.50 +/- 0.40, which is consistent with other ROSAT observations of quasars. However, this average is significantly steeper than suggested by earlier soft X-ray observations of the Einstein IPC. The 0.3 keV flux in our sample can be predicted to better than a factor of 2 once the 1.69 micrometer(s) flux is given. This implies that the X-ray variability power spectra of quasars flattens out between f approximately 10(exp -5) and f

Soft X-ray FEL simulation in PAL-XFEL

NASA Astrophysics Data System (ADS)

Shim, Chi Hyun; Ko, In Soo; Parc, Yong Woon; Han, Jang Hui

2015-10-01

The soft X-ray beamline in the Pohang Accelerator Laboratory X-ray Free Electron Laser (PAL-XFEL) will provide a photon beam with a wavelength from 1 nm to 3 nm in the self-amplified spontaneous emission (SASE) mode by using an electron beam with a 3.15-GeV beam energy. Linearly polarized radiation will be supplied by using six planar undulators (PUs). The linearly-polarized radiation powers at 1 (3) nm can reach 10.2 (30) GW. Polarization of the radiation will be controlled by applying the reverse undulator tapering scheme to the PUs and adding two helical undulators (HUs). The circularly-polarized radiation powers at 1 (3) nm will be 3.11 (11.73) GW. The degrees of circular polarization will be larger than 0.99 for both wavelengths. Three options for the future upgrade of the beamline to increase the radiation power are proposed.

ROSAT observations of pulsed soft X-ray emission from PSR 1055-52

NASA Technical Reports Server (NTRS)

Oegelman, Hakki; Finley, John P.

1993-01-01

Utilizing the position-sensitive proportional counter and the high-resolution imager aboard the orbiting X-ray observatory ROSAT, we have detected pulsations at the radio period from the pulsar PSR 1055-52. The pulse shapes are energy-dependent and show a transition at about 0.5 keV where the phase angle of the pulse peak changes by about -120 deg and the pulsed fraction increases from 11 percent to 63 percent toward larger energies. Simple spectral models are found to be unsatisfactory, while multicomponent models, such as a soft blackbody and hard power-law tail, yield better fits to the pulse-height data. The hard power-law tail is consistent with the extension of the recently reported EGRET results and may indicate a common emission mechanism for the X-ray through GeV gamma-ray regime. The soft blackbody component with T(infinity) = (7.5 +/- 0.6) x 10 exp 5 K, if interpreted as the initial cooling of a neutron star, is consistent with standard cooling models and does not require the presence of exotic components.

On the origin of the soft X-ray background. [in cosmological observations

NASA Technical Reports Server (NTRS)

Wang, Q. D.; Mccray, Richard

1993-01-01

The angular autocorrelation function and spectrum of the soft X-ray background is studied below a discrete source detection limit, using two deep images from the Rosat X-ray satellite. The average spectral shape of pointlike sources, which account for 40 to 60 percent of the background intensity, is determined by using the autocorrelation function. The background spectrum, in the 0.5-0.9 keV band (M band), is decomposed into a pointlike source component characterized by a power law and a diffuse component represented by a two-temperature plasma. These pointlike sources cannot contribute more than 60 percent of the X-ray background intensity in the M band without exceeding the total observed flux in the R7 band. Spectral analysis has shown that the local soft diffuse component, although dominating the background intensity at energies not greater than 0.3 keV, contributes only a small fraction of the M band background intensity. The diffuse component may represent an important constituent of the interstellar or intergalactic medium.

Long pulse Soft X-ray Emission from Laser Generated Irradiated Gold Foils

NASA Astrophysics Data System (ADS)

Davis, Joshua; Frank, Yechiel; Raicher, Erez; Fraenkel, Moshe; Keiter, Paul; Klein, Sallee; Drake, R. P.; Shvarts, Dov

2016-10-01

Long pulse soft x-ray sources (SXS) allow for flexibility in high-energy-density experimental designs by providing a means of driving matter to the high temperatures needed, for example to study radiation waves in different materials. SXSs can be made by using lasers to heat a high-Z thin foil, which then acts as a quasi-blackbody emitter. Previous studies of the x-ray emission characteristics of gold foils have focused on laser pulses of 1ns or less. We performed experiments using a 6.0ns laser pulse with energy of 2kJ on the Omega-60 system to generate and characterize multi-ns laser heated Au foils of thicknesses between 0.5-2.0 μm. We measured the 2D spatial profile of the emission with a soft x-ray camera and the time history of the emission with the Dante photodiode array . Effective temperatures for the emission were then calculated using the Dante measurements. Discussion of experimental results and a comparison with 1-D Rad-Hydro NLTE simulations will be presented.

Revealing the electronic ground state of ReNiO3 combining Ni-L3 x-ray absorption and resonant inelastic x-ray scattering

NASA Astrophysics Data System (ADS)

Bisogni, Valentina; Catalano, Sara; Green, Robert; Gibert, Marta; Scherwitzl, Raoul; Huang, Yaobo; Balandesh, Shadi; Strocov, Vladimir N.; Zubko, Pavlo; Sawatzky, George; Triscone, Jean-Marc; Schmitt, Thorsten

Rare-earth nickelates ReNiO3 attract a lot of interest thanks to their intriguing physical properties like sharp metal to insulator transition, unusual magnetic order and expected superconductivity in nickelate-based heterostructures. Full understanding of these materials, however, is hampered by the difficulties in describing their electronic ground state (GS). Taking a NdNiO3 thin film as a representative example, we reveal with x-ray absorption and resonant inelastic x-ray scattering unusual coexistence of bound and continuum excitations, providing strong evidence for abundant O 2p holes in the GS of these materials. Using an Anderson impurity model interpretation, we show that these distinct spectral signatures arise from a Ni 3d8 configuration along with holes in the O 2p valence band, confirming suggestions that these materials exhibit a negative charge-transfer energy, with O 2p states extending across the Fermi level.

Imaging bacterial spores by soft-x-ray microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stead, A.D.; Ford, T.W.; Judge, J.

1997-04-01

Bacterial spores are able to survive dehydration, but neither the physiological nor structural basis of this have been fully elucidated. Furthermore, once hydrated, spores often require activation before they will germinate. Several treatments can be used to activate spores, but in the case of Bacillus subtlis the most effective is heat treatment. The physiological mechanism associated with activation is also not understood, but some workers suggest that the loss of calcium from the spores may be critical. However, just prior to germination, the spores change from being phase bright to phase dark when viewed by light microscopy. Imaging spores bymore » soft x-ray microscopy is possible without fixation. Thus, in contrast to electron microscopy, it is possible to compare the structure of dehydrated and hydrated spores in a manner not possible previously. A further advantage is that it is possible to monitor individual spores by phase contrast light microscopy immediately prior to imaging with soft x-rays; whereas, with both electron microscopy and biochemical studies, it is a population of spores being studied without knowledge of the phase characteristics of individual spores. This study has therefore tried to compare dehydrated and hydrated spores and to determine if there is a mass loss from individual spores as they pass the transition from being phase bright to phase dark.« less

A DEEP X-RAY VIEW OF THE BARE AGN ARK 120. I. REVEALING THE SOFT X-RAY LINE EMISSION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reeves, J. N.; Braito, V.; Porquet, D.

2016-09-10

The Seyfert 1 galaxy Ark 120 is a prototype example of the so-called class of bare nucleus active galactic nuclei (AGNs), whereby there is no known evidence for the presence of ionized gas along the direct line of sight. Here deep (>400 ks exposure), high-resolution X-ray spectroscopy of Ark 120 is presented from XMM-Newton observations that were carried out in 2014 March, together with simultaneous Chandra /High Energy Transmission Grating exposures. The high-resolution spectra confirmed the lack of intrinsic absorbing gas associated with Ark 120, with the only X-ray absorption present originating from the interstellar medium (ISM) of our ownmore » Galaxy, with a possible slight enhancement of the oxygen abundance required with respect to the expected ISM values in the solar neighborhood. However, the presence of several soft X-ray emission lines are revealed for the first time in the XMM-Newton RGS spectrum, associated with the AGN and arising from the He- and H-like ions of N, O, Ne, and Mg. The He-like line profiles of N, O, and Ne appear velocity broadened, with typical FWHMs of ∼5000 km s{sup −1}, whereas the H-like profiles are unresolved. From the clean measurement of the He-like triplets, we deduce that the broad lines arise from a gas of density n {sub e} ∼ 10{sup 11} cm{sup −3}, while the photoionization calculations infer that the emitting gas covers at least 10% of 4 π steradian. Thus the broad soft X-ray profiles appear coincident with an X-ray component of the optical–UV broad-line region on sub-parsec scales, whereas the narrow profiles originate on larger parsec scales, perhaps coincident with the AGN narrow-line region. The observations show that Ark 120 is not intrinsically bare and substantial X-ray-emitting gas exists out of our direct line of sight toward this AGN.« less

Photospheric soft X-ray emission from hot DA white dwarfs

NASA Technical Reports Server (NTRS)

Wesemael, F.; Raymond, J. C.; Kahn, S. M.; Liebert, J.; Steiner, J. E.; Shipman, H. L.

1984-01-01

The Einstein Observatory's imaging proportional counter has detected 150-eV soft X-ray radiation from the four hot DA white dwarfs EG 187, Gr 288 and 289, and LB 1663. The observed pulse height spectra suggest that the emission is generated by hot photospheres whose T(eff) lie in the 30,000-60,000 K range. The IUE spacecraft UV spectra and H-beta line profiles for the four stars have been fitted, along with the X-ray fluxes, with a grid of hot, high gravity, homogeneous model atmospheres of mixed H-He composition. In all cases, the data require the presence of some X-ray opacity in the photosphere. Attention is given to the implications of this result in the context of white dwarf surface layer diffusion theories. Also noted are the limits imposed on the hot white dwarf population by the Einstein Medium Sensitivity Survey.

Ultraviolet surprise: Efficient soft x-ray high-harmonic generation in multiply ionized plasmas.

PubMed

Popmintchev, Dimitar; Hernández-García, Carlos; Dollar, Franklin; Mancuso, Christopher; Pérez-Hernández, Jose A; Chen, Ming-Chang; Hankla, Amelia; Gao, Xiaohui; Shim, Bonggu; Gaeta, Alexander L; Tarazkar, Maryam; Romanov, Dmitri A; Levis, Robert J; Gaffney, Jim A; Foord, Mark; Libby, Stephen B; Jaron-Becker, Agnieszka; Becker, Andreas; Plaja, Luis; Murnane, Margaret M; Kapteyn, Henry C; Popmintchev, Tenio

2015-12-04

High-harmonic generation is a universal response of matter to strong femtosecond laser fields, coherently upconverting light to much shorter wavelengths. Optimizing the conversion of laser light into soft x-rays typically demands a trade-off between two competing factors. Because of reduced quantum diffusion of the radiating electron wave function, the emission from each species is highest when a short-wavelength ultraviolet driving laser is used. However, phase matching--the constructive addition of x-ray waves from a large number of atoms--favors longer-wavelength mid-infrared lasers. We identified a regime of high-harmonic generation driven by 40-cycle ultraviolet lasers in waveguides that can generate bright beams in the soft x-ray region of the spectrum, up to photon energies of 280 electron volts. Surprisingly, the high ultraviolet refractive indices of both neutral atoms and ions enabled effective phase matching, even in a multiply ionized plasma. We observed harmonics with very narrow linewidths, while calculations show that the x-rays emerge as nearly time-bandwidth-limited pulse trains of ~100 attoseconds. Copyright © 2015, American Association for the Advancement of Science.

Resonant Soft X-ray Scattering of Cellulose Microstructure in Plant Primary Cell Walls

NASA Astrophysics Data System (ADS)

Ye, Dan; Kiemle, Sarah N.; Wang, Cheng; Cosgrove, Daniel J.; Gomez, Esther W.; Gomez, Enrique D.

Cellulosic biomass is the most abundant raw material available for the production of renewable and sustainable biofuels. Breaking down cellulose is the rate-limiting step in economical biofuel production; therefore, a detailed understanding of the microscopic structure of plant cell walls is required to develop efficient biofuel conversion methods. Primary cell walls are key determinants of plant growth and mechanics. Their structure is complex and heterogeneous, making it difficult to elucidate how various components such as pectin, hemicellulose, and cellulose contribute to the overall structure. The electron density of these wall components is similar; such that conventional hard X-ray scattering does not generate enough contrast to resolve the different elements of the polysaccharide network. The chemical specificity of resonant soft X-ray scattering allows contrast to be generated based on differences in chemistry of the different polysaccharides. By varying incident X-ray energies, we have achieved increased scattering contrast between cellulose and other polysaccharides from primary cell walls of onions. By performing scattering at certain energies, features of the network structure of the cell wall are resolved. From the soft X-ray scattering results, we obtained the packing distance of cellulose microfibrils embedded in the polysaccharide network.

Characterization results from several commercial soft X-ray streak cameras

NASA Astrophysics Data System (ADS)

Stradling, G. L.; Studebaker, J. K.; Cavailler, C.; Launspach, J.; Planes, J.

The spatio-temporal performance of four soft X-ray streak cameras has been characterized. The objective in evaluating the performance capability of these instruments is to enable us to optimize experiment designs, to encourage quantitative analysis of streak data and to educate the ultra high speed photography and photonics community about the X-ray detector performance which is available. These measurements have been made collaboratively over the space of two years at the Forge pulsed X-ray source at Los Alamos and at the Ketjak laser facility an CEA Limeil-Valenton. The X-ray pulse lengths used for these measurements at these facilities were 150 psec and 50 psec respectively. The results are presented as dynamically-measured modulation transfer functions. Limiting temporal resolution values were also calculated. Emphasis is placed upon shot noise statistical limitations in the analysis of the data. Space charge repulsion in the streak tube limits the peak flux at ultra short experiments duration times. This limit results in a reduction of total signal and a decrease in signal to no ise ratio in the streak image. The four cameras perform well with 20 1p/mm resolution discernable in data from the French C650X, the Hadland X-Chron 540 and the Hamamatsu C1936X streak cameras. The Kentech X-ray streak camera has lower modulation and does not resolve below 10 1p/mm but has a longer photocathode.

Multilayer films with sharp, stable interfaces for use in EUV and soft X-ray application

DOEpatents

Barbee, Jr., Troy W.; Bajt, Sasa

2002-01-01

The reflectivity and thermal stability of Mo/Si (molybdenum/silicon) multilayer films, used in soft x-ray and extreme ultraviolet region, is enhanced by deposition of a thin layer of boron carbide (e.g., B.sub.4 C) between alternating layers of Mo and Si. The invention is useful for reflective coatings for soft X-ray and extreme ultraviolet optics, multilayer for masks, coatings for other wavelengths and multilayers for masks that are more thermally stable than pure Mo/Si multilayers

A 2 m inelastic x-ray scattering spectrometer at CMC-XOR, Advanced Photon Source.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hill, J. P.; Coburn, D. S.; Kim, Y. J.

2007-07-01

The design and commissioning of an inelastic X-ray scattering instrument at CMC-XOR at the Advanced Photon Source is reported. The instrument features a 2 m vertical-scattering arm with a novel counterweight design to reduce the twisting moment as the arm is moved in the scattering plane. A Ge(733) spherical analyzer was fabricated and an overall resolution of 118 meV (FWHM) was obtained with a Si(444) monochromator and a Si(111) pre-monochromator. Early results from a representative cuprate, La{sub 2}CuO{sub 4}, are reported.

Observations of the structure and evolution of solar flares with a soft X-ray telescope

NASA Technical Reports Server (NTRS)

Vorpahl, J. A.; Gibson, E. G.; Landecker, P. B.; Mckenzie, D. L.; Underwood, J. M.

1975-01-01

Soft X ray flare events were observed with the S-056 X-ray telescope that was part of the ATM complement of instruments aboard SKYLAB. Analyses of these data are reported. The observations are summarized and a detailed discussion of the X-ray flare structures is presented. The data indicated that soft X-ray emitted by a flare come primarily from an intense well-defined core surrounded by a region of fainter, more diffuse emission. An analysis of flare evolution indicates evidence for preliminary heating and energy release prior to the main phase of the flare. Core features are found to be remarkably stable and retain their shape throughout a flare. Most changes in the overall configuration seem to be result of the appearance, disappearance or change in brightness of individual features, rather than the restructuring or reorientation of these features. Brief comparisons with several theories are presented.

Biological soft X-ray tomography on beamline 2.1 at the Advanced Light Source.

PubMed

Le Gros, Mark A; McDermott, Gerry; Cinquin, Bertrand P; Smith, Elizabeth A; Do, Myan; Chao, Weilun L; Naulleau, Patrick P; Larabell, Carolyn A

2014-11-01

Beamline 2.1 (XM-2) is a transmission soft X-ray microscope in sector 2 of the Advanced Light Source at Lawrence Berkeley National Laboratory. XM-2 was designed, built and is now operated by the National Center for X-ray Tomography as a National Institutes of Health Biomedical Technology Research Resource. XM-2 is equipped with a cryogenic rotation stage to enable tomographic data collection from cryo-preserved cells, including large mammalian cells. During data collection the specimen is illuminated with `water window' X-rays (284-543 eV). Illuminating photons are attenuated an order of magnitude more strongly by biomolecules than by water. Consequently, differences in molecular composition generate quantitative contrast in images of the specimen. Soft X-ray tomography is an information-rich three-dimensional imaging method that can be applied either as a standalone technique or as a component modality in correlative imaging studies.

Table-top soft x-ray microscope using laser-induced plasma from a pulsed gas jet.

PubMed

Müller, Matthias; Mey, Tobias; Niemeyer, Jürgen; Mann, Klaus

2014-09-22

An extremely compact soft x-ray microscope operating in the "water window" region at the wavelength λ = 2.88 nm is presented, making use of a long-term stable and nearly debris-free laser-induced plasma from a pulsed nitrogen gas jet target. The well characterized soft x-ray radiation is focused by an ellipsoidal grazing incidence condenser mirror. Imaging of a sample onto a CCD camera is achieved with a Fresnel zone plate using magnifications up to 500x. The spatial resolution of the recorded microscopic images is about 100 nm as demonstrated for a Siemens star test pattern.

Soft x-ray emission from postpulse expanding laser-produced plasmas

NASA Astrophysics Data System (ADS)

Weaver, J. L.; Feldman, U.; Mostovych, A. N.; Seely, J. F.; Colombant, D.; Holland, G.

2003-12-01

A diagnostic spectrometer has been developed at the Naval Research Laboratory to measure the time resolved absolute intensity of radiation emitted from targets irradiated by the Nike laser. The spectrometer consists of a dispersive transmission grating of 2500 lines/mm or 5000 lines/mm and a detection system consisting of an absolutely calibrated Si photodiode array and a charge coupled device camera. In this article, this spectrometer was used to study the spatial distribution of soft x-ray radiation from low Z elements (primarily carbon) that lasted tens of nanoseconds after the main laser illumination was over. We recorded soft x-ray emission as a function of the target material and target orientation with respect to the incoming laser beam and the spectrometer line of sight. While a number of spectral features have been identified in the data, the instrument's combined temporal and spatial resolution allowed observation of the plasma expansion from CH targets for up to ˜25 ns after the cessation of the main laser pulse. The inferred plasma expansion velocities are slightly higher than those previously reported.

ALP conversion and the soft X-ray excess in the outskirts of the Coma cluster

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kraljic, David; Rummel, Markus; Conlon, Joseph P., E-mail: David.Kraljic@physics.ox.ac.uk, E-mail: Markus.Rummel@physics.ox.ac.uk, E-mail: j.conlon1@physics.ox.ac.uk

2015-01-01

It was recently found that the soft X-ray excess in the center of the Coma cluster can be fitted by conversion of axion-like-particles (ALPs) of a cosmic axion background (CAB) to photons. We extend this analysis to the outskirts of Coma, including regions up to 5 Mpc from the center of the cluster. We extract the excess soft X-ray flux from ROSAT All-Sky Survey data and compare it to the expected flux from ALP to photon conversion of a CAB. The soft X-ray excess both in the center and the outskirts of Coma can be simultaneously fitted by ALP tomore » photon conversion of a CAB. Given the uncertainties of the cluster magnetic field in the outskirts we constrain the parameter space of the CAB. In particular, an upper limit on the CAB mean energy and a range of allowed ALP-photon couplings are derived.« less

Nonlinear X-Ray and Auger Spectroscopy at X-Ray Free-Electron Laser Sources

NASA Astrophysics Data System (ADS)

Rohringer, Nina

2015-05-01

X-ray free-electron lasers (XFELs) open the pathway to transfer non-linear spectroscopic techniques to the x-ray domain. A promising all x-ray pump probe technique is based on coherent stimulated electronic x-ray Raman scattering, which was recently demonstrated in atomic neon. By tuning the XFEL pulse to core-excited resonances, a few seed photons in the spectral tail of the XFEL pulse drive an avalanche of resonant inelastic x-ray scattering events, resulting in exponential amplification of the scattering signal by of 6-7 orders of magnitude. Analysis of the line profile of the emitted radiation permits to demonstrate the cross over from amplified spontaneous emission to coherent stimulated resonance scattering. In combination with statistical covariance mapping, a high-resolution spectrum of the resonant inelastic scattering process can be obtained, opening the path to coherent stimulated x-ray Raman spectroscopy. An extension of these ideas to molecules and a realistic feasibility study of stimulated electronic x-ray Raman scattering in CO will be presented. Challenges to realizing stimulated electronic x-ray Raman scattering at present-day XFEL sources will be discussed, corroborated by results of a recent experiment at the LCLS XFEL. Due to the small gain cross section in molecular targets, other nonlinear spectroscopic techniques such as nonlinear Auger spectroscopy could become a powerful alternative. Theory predictions of a novel pump probe technique based on resonant nonlinear Auger spectroscopic will be discussed and the method will be compared to stimulated x-ray Raman spectroscopy.

Resonant magnetic scattering of polarized soft x rays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sacchi, M.; Hague, C.F.; Gullikson, E.M.

1997-04-01

Magnetic effects on X-ray scattering (Bragg diffraction, specular reflectivity or diffuse scattering) are a well known phenomenon, and they also represent a powerful tool for investigating magnetic materials since it was shown that they are strongly enhanced when the photon energy is tuned across an absorption edge (resonant process). The resonant enhancement of the magnetic scattering has mainly been investigated at high photon energies, in order to match the Bragg law for the typical lattice spacings of crystals. In the soft X-ray range, even larger effects are expected, working for instance at the 2p edges of transition metals of themore » first row or at the 3d edges of rare earths (300-1500 eV), but the corresponding long wavelengths prevent the use of single crystals. Two approaches have been recently adopted in this energy range: (i) the study of the Bragg diffraction from artificial structures of appropriate 2d spacing; (ii) the analysis of the specular reflectivity, which contains analogous information but has no constraints related to the lattice spacing. Both approaches have their own specific advantages: for instance, working under Bragg conditions provides information about the (magnetic) periodicity in ordered structures, while resonant reflectivity can easily be related to electronic properties and absorption spectra. An important aspect common to all the resonant X-ray scattering techniques is the element selectivity inherent to the fact of working at a specific absorption edge: under these conditions, X-ray scattering becomes in fact a spectroscopy. Results are presented for films of iron and cobalt.« less

Coherent X-ray diffraction from collagenous soft tissues

PubMed Central

Berenguer de la Cuesta, Felisa; Wenger, Marco P. E.; Bean, Richard J.; Bozec, Laurent; Horton, Michael A.; Robinson, Ian K.

2009-01-01

Coherent X-ray diffraction has been applied in the imaging of inorganic materials with great success. However, its application to biological specimens has been limited to some notable exceptions, due to the induced radiation damage and the extended nature of biological samples, the last limiting the application of most part of the phasing algorithms. X-ray ptychography, still under development, is a good candidate to overcome such difficulties and become a powerful imaging method for biology. We describe herein the feasibility of applying ptychography to the imaging of biological specimens, in particular collagen rich samples. We report here speckles in diffraction patterns from soft animal tissue, obtained with an optimized small angle X-ray setup that exploits the natural coherence of the beam. By phasing these patterns, dark field images of collagen within tendon, skin, bone, or cornea will eventually be obtained with a resolution of 60–70 nm. We present simulations of the contrast mechanism in collagen based on atomic force microscope images of the samples. Simulations confirmed the ‘speckled’ nature of the obtained diffraction patterns. Once inverted, the patterns will show the disposition and orientation of the fibers within the tissue, by enhancing the phase contrast between protein and no protein regions of the sample. Our work affords the application of the most innovative coherent X-ray diffraction tools to the study of biological specimens, and this approach will have a significant impact in biology and medicine because it overcomes many of the limits of current microscopy techniques. PMID:19706395

Coherent X-ray diffraction from collagenous soft tissues.

PubMed

Berenguer de la Cuesta, Felisa; Wenger, Marco P E; Bean, Richard J; Bozec, Laurent; Horton, Michael A; Robinson, Ian K

2009-09-08

Coherent X-ray diffraction has been applied in the imaging of inorganic materials with great success. However, its application to biological specimens has been limited to some notable exceptions, due to the induced radiation damage and the extended nature of biological samples, the last limiting the application of most part of the phasing algorithms. X-ray ptychography, still under development, is a good candidate to overcome such difficulties and become a powerful imaging method for biology. We describe herein the feasibility of applying ptychography to the imaging of biological specimens, in particular collagen rich samples. We report here speckles in diffraction patterns from soft animal tissue, obtained with an optimized small angle X-ray setup that exploits the natural coherence of the beam. By phasing these patterns, dark field images of collagen within tendon, skin, bone, or cornea will eventually be obtained with a resolution of 60-70 nm. We present simulations of the contrast mechanism in collagen based on atomic force microscope images of the samples. Simulations confirmed the 'speckled' nature of the obtained diffraction patterns. Once inverted, the patterns will show the disposition and orientation of the fibers within the tissue, by enhancing the phase contrast between protein and no protein regions of the sample. Our work affords the application of the most innovative coherent X-ray diffraction tools to the study of biological specimens, and this approach will have a significant impact in biology and medicine because it overcomes many of the limits of current microscopy techniques.

The Ultraviolet Surprise. Efficient Soft X-Ray High Harmonic Generation in Multiply-Ionized Plasmas

DOE PAGES

Popmintchev, Dimitar; Hernandez-Garcia, Carlos; Dollar, Franklin; ...

2015-12-04

High-harmonic generation is a universal response of matter to strong femtosecond laser fields, coherently upconverting light to much shorter wavelengths. Optimizing the conversion of laser light into soft x-rays typically demands a trade-off between two competing factors. Reduced quantum diffusion of the radiating electron wave function results in emission from each species which is highest when a short-wavelength ultraviolet driving laser is used. But, phase matching—the constructive addition of x-ray waves from a large number of atoms—favors longer-wavelength mid-infrared lasers. We identified a regime of high-harmonic generation driven by 40-cycle ultraviolet lasers in waveguides that can generate bright beams inmore » the soft x-ray region of the spectrum, up to photon energies of 280 electron volts. Surprisingly, the high ultraviolet refractive indices of both neutral atoms and ions enabled effective phase matching, even in a multiply ionized plasma. We observed harmonics with very narrow linewidths, while calculations show that the x-rays emerge as nearly time-bandwidth–limited pulse trains of ~100 attoseconds.« less

Resonant inelastic X-ray scattering spectrometer with 25meV resolution at the Cu K -edge

DOE PAGES

Ketenoglu, Didem; Harder, Manuel; Klementiev, Konstantin; ...

2015-06-27

An unparalleled resolution is reported with an inelastic X-ray scattering instrument at the CuK-edge. Based on a segmented concave analyzer, featuring single-crystal quartz (SiO 2) pixels, the spectrometer delivers a resolution near 25meV (FWHM) at 8981eV. Besides the quartz analyzer, the performance of the spectrometer relies on a four-bounce Si(553) high-resolution monochromator and focusing Kirkpatrick–Baez optics. The measured resolution agrees with the ray-tracing simulation of an ideal spectrometer. The performance of the spectrometer is demonstrated by reproducing the phonon dispersion curve of a beryllium single-crystal.

Soft X-ray photoemission study of Co2(Cr1-xFex)Ga Heusler compounds

NASA Astrophysics Data System (ADS)

Tsunekawa, Masanori; Hattori, Yoshiro; Sekiyama, Akira; Fujiwara, Hidenori; Suga, Shigemasa; Muro, Takayuki; Kanomata, Takeshi; Imada, Shin

2015-08-01

We have performed soft X-ray photoemission spectroscopy (SXPES) and X-ray absorption spectroscopy (XAS) of the Co-based Heusler compounds Co2(Cr1-xFex)Ga (x = 0.0, 0.4, and 1.0) in order to study their electronic structures. Band-structure calculation was carried out and compared with the experimental results. SXPES spectra show hν-dependence, revealing the contributions of the Co, Cr, and Fe 3d electronic states in the valence band. The band width observed by the SXPES seems to be narrower than that predicted by the band-structure calculation. XAS spectra depend strongly on the the value of x in Co2(Cr1-xFex)Ga. The electron correlation effects are found to be stronger as x changes from 0.0 to 1.0.

Supercrystallization of KCl from solution irradiated by soft X-rays

NASA Astrophysics Data System (ADS)

Janavičius, A. J.; Rinkūnas, R.; Purlys, R.

2016-10-01

The X-rays influence on KCl crystallization in a saturated water solution has been investigated for the aim of comparing it with previously considered NaCl crystallization. The rate of crystallization has been measured in the drying drop in the solution activated by the irradiation. We have measured the influence of the irradiation time of the solution on the rates of KCl crystallization as well as the beginning of the crystallization processes on drying drops. For a longer irradiation time of the solution early crystallization in the drops occurs. A saturated water solution of KCl was irradiated with the diffractometer DRON-3M (Russian device) and this had a great influence on the two-step processes of crystallization. The ionization of the solution by soft X-rays can produce ions, metastable radicals in water, excited crystals' seeds and vacancies in growing crystals by Auger's effect. The X-rays generate a very fast crystallization in the drying drop.

Soft X-ray spectromicroscopy using ptychography with randomly phased illumination

NASA Astrophysics Data System (ADS)

Maiden, A. M.; Morrison, G. R.; Kaulich, B.; Gianoncelli, A.; Rodenburg, J. M.

2013-04-01

Ptychography is a form of scanning diffractive imaging that can successfully retrieve the modulus and phase of both the sample transmission function and the illuminating probe. An experimental difficulty commonly encountered in diffractive imaging is the large dynamic range of the diffraction data. Here we report a novel ptychographic experiment using a randomly phased X-ray probe to considerably reduce the dynamic range of the recorded diffraction patterns. Images can be reconstructed reliably and robustly from this setup, even when scatter from the specimen is weak. A series of ptychographic reconstructions at X-ray energies around the L absorption edge of iron demonstrates the advantages of this method for soft X-ray spectromicroscopy, which can readily provide chemical sensitivity without the need for optical refocusing. In particular, the phase signal is in perfect registration with the modulus signal and provides complementary information that can be more sensitive to changes in the local chemical environment.

Developing a CCD camera with high spatial resolution for RIXS in the soft X-ray range

NASA Astrophysics Data System (ADS)

Soman, M. R.; Hall, D. J.; Tutt, J. H.; Murray, N. J.; Holland, A. D.; Schmitt, T.; Raabe, J.; Schmitt, B.

2013-12-01

The Super Advanced X-ray Emission Spectrometer (SAXES) at the Swiss Light Source contains a high resolution Charge-Coupled Device (CCD) camera used for Resonant Inelastic X-ray Scattering (RIXS). Using the current CCD-based camera system, the energy-dispersive spectrometer has an energy resolution (E/ΔE) of approximately 12,000 at 930 eV. A recent study predicted that through an upgrade to the grating and camera system, the energy resolution could be improved by a factor of 2. In order to achieve this goal in the spectral domain, the spatial resolution of the CCD must be improved to better than 5 μm from the current 24 μm spatial resolution (FWHM). The 400 eV-1600 eV energy X-rays detected by this spectrometer primarily interact within the field free region of the CCD, producing electron clouds which will diffuse isotropically until they reach the depleted region and buried channel. This diffusion of the charge leads to events which are split across several pixels. Through the analysis of the charge distribution across the pixels, various centroiding techniques can be used to pinpoint the spatial location of the X-ray interaction to the sub-pixel level, greatly improving the spatial resolution achieved. Using the PolLux soft X-ray microspectroscopy endstation at the Swiss Light Source, a beam of X-rays of energies from 200 eV to 1400 eV can be focused down to a spot size of approximately 20 nm. Scanning this spot across the 16 μm square pixels allows the sub-pixel response to be investigated. Previous work has demonstrated the potential improvement in spatial resolution achievable by centroiding events in a standard CCD. An Electron-Multiplying CCD (EM-CCD) has been used to improve the signal to effective readout noise ratio achieved resulting in a worst-case spatial resolution measurement of 4.5±0.2 μm and 3.9±0.1 μm at 530 eV and 680 eV respectively. A method is described that allows the contribution of the X-ray spot size to be deconvolved from these

Element Selectivity in Second-Harmonic Generation of GaFeO3 by a Soft-X-Ray Free-Electron Laser

NASA Astrophysics Data System (ADS)

Yamamoto, Sh.; Omi, T.; Akai, H.; Kubota, Y.; Takahashi, Y.; Suzuki, Y.; Hirata, Y.; Yamamoto, K.; Yukawa, R.; Horiba, K.; Yumoto, H.; Koyama, T.; Ohashi, H.; Owada, S.; Tono, K.; Yabashi, M.; Shigemasa, E.; Yamamoto, S.; Kotsugi, M.; Wadati, H.; Kumigashira, H.; Arima, T.; Shin, S.; Matsuda, I.

2018-06-01

Nonlinear optical frequency conversion has been challenged to move down to the extreme ultraviolet and x-ray region. However, the extremely low signals have allowed researchers to only perform transmission experiments of the gas phase or ultrathin films. Here, we report second harmonic generation (SHG) of the reflected beam of a soft x-ray free-electron laser from a solid, which is enhanced by the resonant effect. The observation revealed that the double resonance condition can be met by absorption edges for transition metal oxides in the soft x-ray range, and this suggests that the resonant SHG technique can be applicable to a wide range of materials. We discuss the possibility of element-selective SHG spectroscopy measurements in the soft x-ray range.

Hard-X-Ray/Soft-Gamma-Ray Imaging Sensor Assembly for Astronomy

NASA Technical Reports Server (NTRS)

Myers, Richard A.

2008-01-01

An improved sensor assembly has been developed for astronomical imaging at photon energies ranging from 1 to 100 keV. The assembly includes a thallium-doped cesium iodide scintillator divided into pixels and coupled to an array of high-gain avalanche photodiodes (APDs). Optionally, the array of APDs can be operated without the scintillator to detect photons at energies below 15 keV. The array of APDs is connected to compact electronic readout circuitry that includes, among other things, 64 independent channels for detection of photons in various energy ranges, up to a maximum energy of 100 keV, at a count rate up to 3 kHz. The readout signals are digitized and processed by imaging software that performs "on-the-fly" analysis. The sensor assembly has been integrated into an imaging spectrometer, along with a pair of coded apertures (Fresnel zone plates) that are used in conjunction with the pixel layout to implement a shadow-masking technique to obtain relatively high spatial resolution without having to use extremely small pixels. Angular resolutions of about 20 arc-seconds have been measured. Thus, for example, the imaging spectrometer can be used to (1) determine both the energy spectrum of a distant x-ray source and the angular deviation of the source from the nominal line of sight of an x-ray telescope in which the spectrometer is mounted or (2) study the spatial and temporal development of solar flares, repeating - ray bursters, and other phenomena that emit transient radiation in the hard-x-ray/soft- -ray region of the electromagnetic spectrum.

Measurement of collective excitations in VO 2 by resonant inelastic x-ray scattering

DOE PAGES

He, Haowei; Gray, A. X.; Granitzka, P.; ...

2016-10-15

Vanadium dioxide is of broad interest as a spin-1/2 electron system that realizes a metal-insulator transition near room temperature, due to a combination of strongly correlated and itinerant electron physics. Here, resonant inelastic x-ray scattering is used to measure the excitation spectrum of charge and spin degrees of freedom at the vanadium L edge under different polarization and temperature conditions, revealing excitations that differ greatly from those seen in optical measurements. Furthermore, these spectra encode the evolution of short-range energetics across the metal-insulator transition, including the low-temperature appearance of a strong candidate for the singlet-triplet excitation of a vanadium dimer.

Biological soft X-ray tomography on beamline 2.1 at the Advanced Light Source

PubMed Central

Le Gros, Mark A.; McDermott, Gerry; Cinquin, Bertrand P.; Smith, Elizabeth A.; Do, Myan; Chao, Weilun L.; Naulleau, Patrick P.; Larabell, Carolyn A.

2014-01-01

Beamline 2.1 (XM-2) is a transmission soft X-ray microscope in sector 2 of the Advanced Light Source at Lawrence Berkeley National Laboratory. XM-2 was designed, built and is now operated by the National Center for X-ray Tomography as a National Institutes of Health Biomedical Technology Research Resource. XM-2 is equipped with a cryogenic rotation stage to enable tomographic data collection from cryo-preserved cells, including large mammalian cells. During data collection the specimen is illuminated with ‘water window’ X-rays (284–543 eV). Illuminating photons are attenuated an order of magnitude more strongly by biomolecules than by water. Consequently, differences in molecular composition generate quantitative contrast in images of the specimen. Soft X-ray tomography is an information-rich three-dimensional imaging method that can be applied either as a standalone technique or as a component modality in correlative imaging studies. PMID:25343808

A Compact Soft X-Ray Microscope using an Electrode-less Z-Pinch Source.

PubMed

Horne, S F; Silterra, J; Holber, W

2009-01-01

Soft X-rays (< 1Kev) are of medical interest both for imaging and microdosimetry applications. X-ray sources at this low energy present a technological challenge. Synchrotrons, while very powerful and flexible, are enormously expensive national research facilities. Conventional X-ray sources based on electron bombardment can be compact and inexpensive, but low x-ray production efficiencies at low electron energies restrict this approach to very low power applications. Laser-based sources tend to be expensive and unreliable. Energetiq Technology, Inc. (Woburn, MA, USA) markets a 92 eV, 10W(2pi sr) electrode-less Z-pinch source developed for advanced semiconductor lithography. A modified version of this commercial product has produced 400 mW at 430 eV (2pi sr), appropriate for water window soft X-ray microscopy. The US NIH has funded Energetiq to design and construct a demonstration microscope using this source, coupled to a condenser optic, as the illumination system. The design of the condenser optic matches the unique characteristics of the source to the illumination requirements of the microscope, which is otherwise a conventional design. A separate program is underway to develop a microbeam system, in conjunction with the RARAF facility at Columbia University, NY, USA. The objective is to develop a focused, sub-micron beam capable of delivering > 1 Gy/second to the nucleus of a living cell. While most facilities of this type are coupled to a large and expensive particle accelerator, the Z-pinch X-ray source enables a compact, stand-alone design suitable to a small laboratory. The major technical issues in this system involve development of suitable focusing X-ray optics. Current status of these programs will be reported.

A Compact Soft X-Ray Microscope using an Electrode-less Z-Pinch Source

PubMed Central

Silterra, J; Holber, W

2009-01-01

Soft X-rays (< 1Kev) are of medical interest both for imaging and microdosimetry applications. X-ray sources at this low energy present a technological challenge. Synchrotrons, while very powerful and flexible, are enormously expensive national research facilities. Conventional X-ray sources based on electron bombardment can be compact and inexpensive, but low x-ray production efficiencies at low electron energies restrict this approach to very low power applications. Laser-based sources tend to be expensive and unreliable. Energetiq Technology, Inc. (Woburn, MA, USA) markets a 92 eV, 10W(2pi sr) electrode-less Z-pinch source developed for advanced semiconductor lithography. A modified version of this commercial product has produced 400 mW at 430 eV (2pi sr), appropriate for water window soft X-ray microscopy. The US NIH has funded Energetiq to design and construct a demonstration microscope using this source, coupled to a condenser optic, as the illumination system. The design of the condenser optic matches the unique characteristics of the source to the illumination requirements of the microscope, which is otherwise a conventional design. A separate program is underway to develop a microbeam system, in conjunction with the RARAF facility at Columbia University, NY, USA. The objective is to develop a focused, sub-micron beam capable of delivering > 1 Gy/second to the nucleus of a living cell. While most facilities of this type are coupled to a large and expensive particle accelerator, the Z-pinch X-ray source enables a compact, stand-alone design suitable to a small laboratory. The major technical issues in this system involve development of suitable focusing X-ray optics. Current status of these programs will be reported. PMID:20198115

Soft x-ray imager (SXI) onboard the NeXT satellite

NASA Astrophysics Data System (ADS)

Tsuru, Takeshi Go; Takagi, Shin-Ichiro; Matsumoto, Hironori; Inui, Tatsuya; Ozawa, Midori; Koyama, Katsuji; Tsunemi, Hiroshi; Hayashida, Kiyoshi; Miyata, Emi; Ozawa, Hideki; Touhiguchi, Masakuni; Matsuura, Daisuke; Dotani, Tadayasu; Ozaki, Masanobu; Murakami, Hiroshi; Kohmura, Takayoshi; Kitamoto, Shunji; Awaki, Hisamitsu

2006-06-01

We give overview and the current status of the development of the Soft X-ray Imager (SXI) onboard the NeXT satellite. SXI is an X-ray CCD camera placed at the focal plane detector of the Soft X-ray Telescopes for Imaging (SXT-I) onboard NeXT. The pixel size and the format of the CCD is 24 x 24μm (IA) and 2048 x 2048 x 2 (IA+FS). Currently, we have been developing two types of CCD as candidates for SXI, in parallel. The one is front illumination type CCD with moderate thickness of the depletion layer (70 ~ 100μm) as a baseline plan. The other one is the goal plan, in which we develop back illumination type CCD with a thick depletion layer (200 ~ 300μm). For the baseline plan, we successfully developed the proto model 'CCD-NeXT1' with the pixel size of 12μm x 12μm and the CCD size of 24mm x 48mm. The depletion layer of the CCD has reached 75 ~ 85μm. The goal plan is realized by introduction of a new type of CCD 'P-channel CCD', which collects holes in stead of electrons in the common 'N-channel CCD'. By processing a test model of P-channel CCD we have confirmed high quantum efficiency above 10 keV with an equivalent depletion layer of 300μm. A back illumination type of P-channel CCD with a depletion layer of 200μm with aluminum coating for optical blocking has been also successfully developed. We have been also developing a thermo-electric cooler (TEC) with the function of the mechanically support of the CCD wafer without standoff insulators, for the purpose of the reduction of thermal input to the CCD through the standoff insulators. We have been considering the sensor housing and the onboard electronics for the CCD clocking, readout and digital processing of the frame date.

Tin-polyimide and indium-polyimide thin-film composites as soft X-ray bandpass filters

NASA Technical Reports Server (NTRS)

Powell, Stephen F.; Allen, Maxwell J.; Willis, Thomas D.

1993-01-01

A tin-polyimide and an indium-polyimide soft X-ray bandpass filter were fabricated with thicknesses of 1400 and 1750 A for the metal and polyimide components, respectively. The transmission of each filter was measured at the Stanford Synchrotron Radiation Laboratory. The transmission of the tin-polyimide filter was found to be about 40 percent for radiation with wavelengths between 60 and 80 A. The transmission of the indium-polyimide filter was greater than 40 percent between 70 and 90 A. The indium was about 5 percent more transmissive than the tin and attained a maximum transmission of about 48 percent at 76 A. Such filters have potential applications to soft X-ray telescopes that operate in this region. They might also be of interest to investigators who work with X-ray microscopes that image live biological specimens in the 23-44-A water window.

Soft x rays as a tool to investigate radiation-sensitive sites in mammalian cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brenner, D.J.; Zaider, M.

1983-01-01

It is now clear that the initial geometrical distribution of primary radiation products in irradiated biological matter is fundamental to the observed end point (cell killing, mutation induction, chromosome aberrations, etc.). In recent years much evidence has accumulated indicating that for all radiations, physical quantities averaged over cellular dimensions (micrometers) are not good predictors of biological effect, and that energy-deposition processes at the nanometer level are critical. Thus irradiation of cells with soft x rays whose secondary electrons have ranges of the order of nanometers is a unique tool for investigating different models for predicting the biological effects of radiation.more » We demonstrate techniques whereby the biological response of the cell and the physical details of the energy deposition processes may be separated or factorized, so that given the response of a cellular system to, say, soft x rays, the response of the cell to any other radiation may be predicted. The special advantages of soft x rays for eliciting this information and also information concerning the geometry of the radiation sensitive structures within the cell are discussed.« less

GAMMA-RAY OBSERVATIONS OF CYGNUS X-1 ABOVE 100 MeV IN THE HARD AND SOFT STATES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sabatini, S.; Tavani, M.; Del Santo, M.

2013-04-01

We present the results of multi-year gamma-ray observations by the AGILE satellite of the black hole binary system Cygnus X-1. In a previous investigation we focused on gamma-ray observations of Cygnus X-1 in the hard state during the period mid-2007/2009. Here we present the results of the gamma-ray monitoring of Cygnus X-1 during the period 2010/mid-2012 which includes a remarkably prolonged 'soft state' phase (2010 June-2011 May). Previous 1-10 MeV observations of Cyg X-1 in this state hinted at a possible existence of a non-thermal particle component with substantial modifications of the Comptonized emission from the inner accretion disk. Ourmore » AGILE data, averaged over the mid-2010/mid-2011 soft state of Cygnus X-1, provide a significant upper limit for gamma-ray emission above 100 MeV of F{sub soft} < 20 Multiplication-Sign 10{sup -8} photons cm{sup -2} s{sup -1} , excluding the existence of prominent non-thermal emission above 100 MeV during the soft state of Cygnus X-1. We discuss theoretical implications of our findings in the context of high-energy emission models of black hole accretion. We also discuss possible gamma-ray flares detected by AGILE. In addition to a previously reported episode observed by AGILE in 2009 October during the hard state, we report a weak but important candidate for enhanced emission which occurred at the end of 2010 June (2010 June 30 10:00-2010 July 2 10:00 UT) exactly coinciding with a hard-to-soft state transition and before an anomalous radio flare. An appendix summarizes all previous high-energy observations and possible detections of Cygnus X-1 above 1 MeV.« less

Normal-incidence soft X-ray telescopes

NASA Technical Reports Server (NTRS)

Spiller, Eberhard; Mccorkle, R. A.; Wilczynski, J. S.; Golub, Leon; Nystrom, G.; Takacs, P. Z.; Welch, C.

1991-01-01

Photos obtained during 5 min of observation time from the flight of a 25-cm-diameter normal-incidence soft-X-ray (63.5 A) telescope on September 11, 1989, are analyzed, and the data are compared to the results expected from tests of the mirror surfaces. These tests cover a range of spatial periods from 25 cm to 1 A. The photos demonstrate a resolution close to the photon shot-noise limit and a reduction in the scattering of the multilayer mirror compared to a single surface for scattering angles above 1 arcmin, corrresponding to surface irregularities with spatial periods below 10 microns. These results are used to predict the possible performance of future telescopes. Sounding rocket observations might be able to reach a resolution around 0.1 arcsec.

Structure and collective dynamics of hydrated anti-freeze protein type III from 180 K to 298 K by X-ray diffraction and inelastic X-ray scattering

NASA Astrophysics Data System (ADS)

Yoshida, Koji; Baron, Alfred Q. R.; Uchiyama, Hiroshi; Tsutsui, Satoshi; Yamaguchi, Toshio

2016-04-01

We investigated hydrated antifreeze protein type III (AFP III) powder with a hydration level h (=mass of water/mass of protein) of 0.4 in the temperature range between 180 K and 298 K using X-ray diffraction and inelastic X-ray scattering (IXS). The X-ray diffraction data showed smooth, largely monotonic changes between 180 K and 298 K without freezing water. Meanwhile, the collective dynamics observed by IXS showed a strong change in the sound velocity at 180 K, after being largely temperature independent at higher temperatures (298-220 K). We interpret this change in terms of the dynamic transition previously discussed using other probes including THz IR absorption spectroscopy and incoherent elastic and quasi-elastic neutron scattering. This finding suggests that the dynamic transition of hydrated proteins is observable on the subpicosecond time scale as well as nano- and pico-second scales, both in collective dynamics from IXS and single particle dynamics from neutron scattering. Moreover, it is most likely that the dynamic transition of hydrated AFP III is not directly correlated with its hydration structure.

Structure and collective dynamics of hydrated anti-freeze protein type III from 180 K to 298 K by X-ray diffraction and inelastic X-ray scattering.

PubMed

Yoshida, Koji; Baron, Alfred Q R; Uchiyama, Hiroshi; Tsutsui, Satoshi; Yamaguchi, Toshio

2016-04-07

We investigated hydrated antifreeze protein type III (AFP III) powder with a hydration level h (=mass of water/mass of protein) of 0.4 in the temperature range between 180 K and 298 K using X-ray diffraction and inelastic X-ray scattering (IXS). The X-ray diffraction data showed smooth, largely monotonic changes between 180 K and 298 K without freezing water. Meanwhile, the collective dynamics observed by IXS showed a strong change in the sound velocity at 180 K, after being largely temperature independent at higher temperatures (298-220 K). We interpret this change in terms of the dynamic transition previously discussed using other probes including THz IR absorption spectroscopy and incoherent elastic and quasi-elastic neutron scattering. This finding suggests that the dynamic transition of hydrated proteins is observable on the subpicosecond time scale as well as nano- and pico-second scales, both in collective dynamics from IXS and single particle dynamics from neutron scattering. Moreover, it is most likely that the dynamic transition of hydrated AFP III is not directly correlated with its hydration structure.

A multi-frame soft x-ray pinhole imaging diagnostic for single-shot applicationsa)

NASA Astrophysics Data System (ADS)

Wurden, G. A.; Coffey, S. K.

2012-10-01

For high energy density magnetized target fusion experiments at the Air Force Research Laboratory FRCHX machine, obtaining multi-frame soft x-ray images of the field reversed configuration (FRC) plasma as it is being compressed will provide useful dynamics and symmetry information. However, vacuum hardware will be destroyed during the implosion. We have designed a simple in-vacuum pinhole nosecone attachment, fitting onto a Conflat window, coated with 3.2 mg/cm2 of P-47 phosphor, and covered with a thin 50-nm aluminum reflective overcoat, lens-coupled to a multi-frame Hadland Ultra intensified digital camera. We compare visible and soft x-ray axial images of translating (˜200 eV) plasmas in the FRX-L and FRCHX machines in Los Alamos and Albuquerque.

Analysis of solar X-ray data

NASA Technical Reports Server (NTRS)

Teske, R. G.

1972-01-01

Type III solar bursts occurring in the absence of solar flares were observed to be accompanied by weak X-radiation. The energy scale of an OSO-3 soft X-ray ion chamber was assessed using realistic theoretical X-ray spectra. Relationships between soft solar X-rays and solar activity were investigated. These included optical studies, the role of the Type III acceleration mechanism in establishing the soft X-ray source volume, H alpha flare intensity variations, and gross magnetic field structure.

Modeling the focusing efficiency of lobster-eye optics for image shifting depending on the soft x-ray wavelength.

PubMed

Su, Luning; Li, Wei; Wu, Mingxuan; Su, Yun; Guo, Chongling; Ruan, Ningjuan; Yang, Bingxin; Yan, Feng

2017-08-01

Lobster-eye optics is widely applied to space x-ray detection missions and x-ray security checks for its wide field of view and low weight. This paper presents a theoretical model to obtain spatial distribution of focusing efficiency based on lobster-eye optics in a soft x-ray wavelength. The calculations reveal the competition mechanism of contributions to the focusing efficiency between the geometrical parameters of lobster-eye optics and the reflectivity of the iridium film. In addition, the focusing efficiency image depending on x-ray wavelengths further explains the influence of different geometrical parameters of lobster-eye optics and different soft x-ray wavelengths on focusing efficiency. These results could be beneficial to optimize parameters of lobster-eye optics in order to realize maximum focusing efficiency.

The Geminga Pulsar: Soft X-Ray Variability and an EUVE Observation

NASA Technical Reports Server (NTRS)

Halpern, Jules P.; Martin, Christopher; Marshall, Herman L.; Oliversen, Ronald (Technical Monitor)

2001-01-01

We observed the Geminga pulsar with the EUVE satellite, detecting pulsed emission in the Deep Survey imager. Joint spectral fits of the EUVE flux with ROSAT PSPC data are consistent with thermal plus power-law models in which the thermal component makes the dominant contribution to the soft X-ray flux seen by EUVE and ROSAT. The data are consistent with blackbody emission of T = (4 - 6) x 10(exp 5) K over most of the surface of the star at the measured parallax distance of 160 pc. Although model atmospheres are more realistic, and can fit the data with effective temperatures a factor of 2 lower, current data would not discriminate between these and blackbody models. We also find evidence for variability of Geminga's soft X-ray pulse shape. Narrow dips in the light curve that were present in 1991 had largely disappeared in 1993/1994, causing the pulsed fraction to decline from 32% to 18%. If the dips are attributed to cyclotron resonance scattering by an e1 plasma on closed magnetic field lines, then the process that resupplies that plasma must be variable.

The Geminga Pulsar: Soft X-Ray Variability and an EUVE Observation

NASA Technical Reports Server (NTRS)

Halpern, Jules P.; Martin, Christopher; Marshall, Herman L.

1996-01-01

We observed the Geminga pulsar with the EUVE satellite, detecting pulsed emission in the Deep Survey imager. Joint spectral fits of the EUVE flux with ROSAT PSPC data are consistent with thermal plus power-law models in which the thermal component makes the dominant contribution to the soft X-ray flux seen by EUVE and ROSAT. The data are consistent with blackbody emission of T = (4-6) x 10(exp 5) K over most of the surface of the star at the measured parallax distance of 160 pc. Although model atmospheres are more realistic, and can fit the data with effective temperatures a factor of 2 lower, current data would not discriminate between these and blackbody models. We also find evidence for variability of Geminga's soft X-ray pulse shape. Narrow dips in the light curve that were present in 1991 had largely disappeared in 1993/1994, causing the pulsed fraction to decline from 32% to 18%. If the dips are attributed to cyclotron resonance scattering by an e(+/-) plasma on closed magnetic field lines, then the process that resupplies that plasma must be variable.

Charge-Transfer Analysis of 2p3d Resonant Inelastic X-ray Scattering of Cobalt Sulfide and Halides

PubMed Central

2017-01-01

We show that with 2p3d resonant inelastic X-ray scattering (RIXS) we can accurately determine the charge-transfer parameters of CoF2, CoCl2, CoBr2, and CoS. The 160 meV resolution RIXS results are compared with charge-transfer multiplet calculations. The improved resolution and the direct observation of the crystal field and charge-transfer excitations allow the determination of more accurate parameters than could be derived from X-ray absorption and X-ray photoemission, both limited in resolution by their lifetime broadening. We derive the crystal field and charge-transfer parameters of the Co2+ ions, which provides the nature of the ground state of the Co2+ ions with respect to symmetry and hybridization. In addition, the increased spectral resolution allows the more accurate determination of the atomic Slater integrals. The results show that the crystal field energy decreases with increasing ligand covalency. The L2 edge RIXS spectra show that the intensity of the (Coster–Kronig induced) nonresonant X-ray emission is a measure of ligand covalency. PMID:29170686

Absolute Soft X-ray Emission Measurements at the Nike Laser

NASA Astrophysics Data System (ADS)

Weaver, J.; Atkin, R.; Boyer, C.; Colombant, D.; Feldman, U.; Fielding, D.; Gardner, J.; Holland, G.; Klapisch, M.; Mostovych, A. N.; Obenscain, S.; Seely, J. F.

2002-11-01

Recent experiments at the Nike laser facility have demonstrated that, when a low intensity prepulse ( 2main laser intensity) is used to heat a thin Au or Pd coating on a planar CH target, the growth of non-uniformities due to laser imprint can be reduced from the growth observed for an uncoated CH target. The absolute radiation intensity in the soft x-ray region (0.1-1 keV) has a important role in the energy balance for layered targets. There is an ongoing effort to characterize the soft x-ray emission using an absolutely calibrated transmission grating spectrometer and filtered diode modules. Measurements of the angular distribution of the emission from unlayered solid targets (Au, Pd, CH) have recently been made using an array of moveable filtered diode modules. The data from the angular distribution studies will be presented. A new absolutely calibrated, time-resolving transmission grating spectrometer has been installed at the Nike. The new version has improved spectral resolution, selectable transmission filters, and the potential for simultaneous temporal, spatial, and spectral resolution. Preliminary data from the new spectrometer will be presented and future experiments will be briefly discussed. *Work was supported by DoE

Probing single magnon excitations in Sr₂IrO₄ using O K-edge resonant inelastic x-ray scattering.

PubMed

Liu, X; Dean, M P M; Liu, J; Chiuzbăian, S G; Jaouen, N; Nicolaou, A; Yin, W G; Rayan Serrao, C; Ramesh, R; Ding, H; Hill, J P

2015-05-27

Resonant inelastic x-ray scattering (RIXS) at the L-edge of transition metal elements is now commonly used to probe single magnon excitations. Here we show that single magnon excitations can also be measured with RIXS at the K-edge of the surrounding ligand atoms when the center heavy metal elements have strong spin-orbit coupling. This is demonstrated with oxygen K-edge RIXS experiments on the perovskite Sr2IrO4, where low energy peaks from single magnon excitations were observed. This new application of RIXS has excellent potential to be applied to a wide range of magnetic systems based on heavy elements, for which the L-edge RIXS energy resolution in the hard x-ray region is usually poor.

The Soft X-ray Imager (SXI) for the ASTRO-H Mission

NASA Astrophysics Data System (ADS)

Tanaka, Takaaki; Tsunemi, Hiroshi; Hayashida, Kiyoshi; Tsuru, Takeshi G.; Dotani, Tadayasu; Nakajima, Hiroshi; Anabuki, Naohisa; Nagino, Ryo; Uchida, Hiroyuki; Nobukawa, Masayoshi; Ozaki, Masanobu; Natsukari, Chikara; Tomida, Hiroshi; Ueda, Shutaro; Kimura, Masashi; Hiraga, Junko S.; Kohmura, Takayoshi; Murakami, Hiroshi; Mori, Koji; Yamauchi, Makoto; Hatsukade, Isamu; Nishioka, Yusuke; Bamba, Aya; Doty, John P.

2015-09-01

The Soft X-ray Imager (SXI) is an X-ray CCD camera onboard the ASTRO-H X-ray observatory. The CCD chip used is a P-channel back-illuminated type, and has a 200-µm thick depletion layer, with which the SXI covers the energy range between 0.4 keV and 12 keV. Its imaging area has a size of 31 mm x 31 mm. We arrange four of the CCD chips in a 2 by 2 grid so that we can cover a large field-of-view of 38' x 38'. We cool the CCDs to -120 °C with a single-stage Stirling cooler. As was done for the CCD camera of the Suzaku satellite, XIS, artificial charges are injected to selected rows in order to recover charge transfer inefficiency due to radiation damage caused by in-orbit cosmic rays. We completed fabrication of flight models of the SXI and installed them into the satellite. We verified the performance of the SXI in a series of satellite tests. On-ground calibrations were also carried out and detailed studies are ongoing.

On the Origin of the Soft X-ray excess in radio quiet AGN

NASA Astrophysics Data System (ADS)

Petrucci, P.; Ursini, F.; Cappi, M.; Bianchi, S.; Matt, G.; De Rosa, A.; Malzac, J.; Henri, G.

2016-06-01

Known since the 80s, the origin of the soft X-ray (< 2 keV) emission in excess to the high energy (2-10 keV) power law extrapolation, the so-called soft X-ray excess, is still highly debated. Two models are commonly discussed: relativistically blurred ionized reflection or thermal comptonisation. In some objects the observation of UV-soft X-ray correlation and the absence of clear signature of relativistic broadening, suggests comptonization as the dominant process. We successfully tested this hypothesis during the 2009 broad band monitoring campaign of Mkn 509. The deduced properties of the comptonizing plasma suggest a warm (˜1 keV), moderately thick (tau˜10-20) corona covering a large part of the accretion disk. Interestingly, the disc-corona energetics agree with a passive accretion disc, most of the accretion power being released in the warm corona. In this talk I will present the results obtained applying the same method to a sample of objects selected to have: a) 3 XMM observations b) at least 3 OM filters in use and c) a low (<1.e22 cm-2) neutral absorption. They all agree with a powerful warm corona above a passive or almost passive accretion disk. I will discuss the methodology and the important implications of the results.

In-flight calibration of the Hitomi Soft X-ray Spectrometer. (2) Point spread function

NASA Astrophysics Data System (ADS)

Maeda, Yoshitomo; Sato, Toshiki; Hayashi, Takayuki; Iizuka, Ryo; Angelini, Lorella; Asai, Ryota; Furuzawa, Akihiro; Kelley, Richard; Koyama, Shu; Kurashima, Sho; Ishida, Manabu; Mori, Hideyuki; Nakaniwa, Nozomi; Okajima, Takashi; Serlemitsos, Peter J.; Tsujimoto, Masahiro; Yaqoob, Tahir

2018-03-01

We present results of inflight calibration of the point spread function of the Soft X-ray Telescope that focuses X-rays onto the pixel array of the Soft X-ray Spectrometer system. We make a full array image of a point-like source by extracting a pulsed component of the Crab nebula emission. Within the limited statistics afforded by an exposure time of only 6.9 ks and limited knowledge of the systematic uncertainties, we find that the raytracing model of 1 {^'.} 2 half-power-diameter is consistent with an image of the observed event distributions across pixels. The ratio between the Crab pulsar image and the raytracing shows scatter from pixel to pixel that is 40% or less in all except one pixel. The pixel-to-pixel ratio has a spread of 20%, on average, for the 15 edge pixels, with an averaged statistical error of 17% (1 σ). In the central 16 pixels, the corresponding ratio is 15% with an error of 6%.

Optical performance of W/B4C multilayer mirror in the soft x-ray region

NASA Astrophysics Data System (ADS)

Pradhan, P. C.; Majhi, A.; Nayak, M.

2018-03-01

W/B4C x-ray multilayers (MLs) with 300 layer pairs and a period in the range of d = 2-1.6 nm are fabricated and investigated for the x-ray optical element in the soft x-ray regime. The structural analyses of the MLs are carried out by using hard x-ray reflectivity (HXR) measurements at 8.047 keV. Well-defined successive higher order Bragg peaks (up to 3rd order) in HXR data collected up to glancing incidence angles of ˜9° reveal a good quality of the periodic structure. The ML mirrors have an average interface width of ˜0.35 nm and have a compressive residual stress of ˜0.183 GPa and 0. 827 GPa for d = 1.62 nm and d = 1.98 nm, respectively. MLs maintain structural stability over a long time, with a slight increase in interface widths of the W layers by 0.1 nm due to self-diffusion. Soft x-ray reflectivity (SXR) performances are evaluated in the energy range of 650 to 1500 eV. At energy ˜ 1489 eV, measured reflectivities (energy resolution, ΔE) are ˜ 10% (19 eV) and 4.5% (13 eV) at glancing incident angles of 12.07° and 15° for MLs having periods of 1.98 nm and 1.62 nm, respectively. The optical performance from 1600 eV to 4500 eV is theoretically analysed by considering the measured structural parameters. The structure-stress-optical performance is correlated on the basis of the mechanism of film growth. The implications of W/B4C MLs are discussed, particularly with respect to the development of ML optics with high spectral selectivity and reflectance for soft x-ray instruments.

Inelastic X-ray scattering of RTAl3 (R = La, Ce, T = Cu, Au)

NASA Astrophysics Data System (ADS)

Tsutsui, Satoshi; Kaneko, Koji; Pospisil, Jiri; Haga, Yoshinori

2018-05-01

Inelastic X-ray scattering (IXS) experiments of RTAl3 (R = La Ce, T = Cu, Au) were carried out at 300 and 5.5 K. The spectra between LaCuAl3 and CeCuAl3 (LaAuAl3 and CeAuAl3) are nearly identical at both temperatures except for temperature factors such as temperature dependence of Bose factor in IXS spectra and effect on thermal expansion. This means that no evident temperature dependence of IXS spectra was observed in CeTAl3 (T = Cu, Au). Since the major contribution of scattering cross section in IXS measurements is Thomson scattering, the present results failed to confirm the presence of vibron in these compounds.

Inelastic x-ray scattering measurements of phonon dynamics in URu 2Si 2

DOE PAGES

Gardner, D. R.; Bonnoit, C. J.; Chisnell, R.; ...

2016-02-11

In this paper, we study high-resolution inelastic x-ray scattering measurements of the acoustic phonons of URu 2Si 2. At all temperatures, the longitudinal acoustic phonon linewidths are anomalously broad at small wave vectors revealing a previously unknown anharmonicity. The phonon modes do not change significantly upon cooling into the hidden order phase. In addition, our data suggest that the increase in thermal conductivity in the hidden order phase cannot be driven by a change in phonon dispersions or lifetimes. Hence, the phonon contribution to the thermal conductivity is likely much less significant compared to that of the magnetic excitations inmore » the low temperature phase.« less

Distribution of lifetimes for coronal soft X-ray bright points

NASA Technical Reports Server (NTRS)

Golub, L.; Krieger, A. S.; Vaiana, G. S.

1976-01-01

The lifetime 'spectrum' of X-ray bright points (XBPs) is measured for a sample of 300 such features using soft X-ray images obtained with the S-054 X-ray spectrographic telescope aboard Skylab. 'Spectrum' here is defined as a function which gives the relative number of XBPs having a specific lifetime as a function of lifetime. The results indicate that a two-lifetime exponential can be fit to the decay curves of XBPs, that the spectrum is heavily weighted toward short lifetimes, and that the number of features lasting 20 to 30 hr or more is greater than expected. A short-lived component with an average lifetime of about 8 hr and a long-lived 1.5-day component are consistently found along with a few features lasting 50 hr or more. An examination of differences among the components shows that features lasting 2 days or less have a broad heliocentric-latitude distribution while nearly all the longer-lived features are observed within 30 deg of the solar equator.

Generation of subterawatt-attosecond pulses in a soft x-ray free-electron laser

DOE PAGES

Huang, Senlin; Ding, Yuantao; Huang, Zhirong; ...

2016-08-15

Here, we propose a novel scheme to generate attosecond soft x rays in a self-seeded free-electron laser (FEL) suitable for enabling attosecond spectroscopic investigations. A time-energy chirped electron bunch with additional sinusoidal energy modulation is adopted to produce a short seed pulse through a self-seeding monochromator. This short seed pulse, together with high electron current spikes and a cascaded delay setup, enables a high-efficiency FEL with a fresh bunch scheme. Simulations show that using the Linac Coherent Light Source (LCLS) parameters, soft x-ray pulses with a FWHM of 260 attoseconds and a peak power of 0.5 TW can be obtained.more » This scheme also has the feature of providing a stable central wavelength determined by the self-seeding monochromator.« less

A multi-frame soft x-ray pinhole imaging diagnostic for single-shot applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wurden, G. A.; Coffey, S. K.

2012-10-15

For high energy density magnetized target fusion experiments at the Air Force Research Laboratory FRCHX machine, obtaining multi-frame soft x-ray images of the field reversed configuration (FRC) plasma as it is being compressed will provide useful dynamics and symmetry information. However, vacuum hardware will be destroyed during the implosion. We have designed a simple in-vacuum pinhole nosecone attachment, fitting onto a Conflat window, coated with 3.2 mg/cm{sup 2} of P-47 phosphor, and covered with a thin 50-nm aluminum reflective overcoat, lens-coupled to a multi-frame Hadland Ultra intensified digital camera. We compare visible and soft x-ray axial images of translating ({approx}200more » eV) plasmas in the FRX-L and FRCHX machines in Los Alamos and Albuquerque.« less

Nonrelativistic quantum theory of the contact inelastic scattering of an x-ray photon by an atom

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hopersky, Alexey N.; Nadolinsky, Alexey M.

The nonrelativistic analytical structure of the doubly differential cross section of the contact inelastic scattering of an x-ray photon by a free atom is determined by means of the irreducible tensor operator theory outside the frame of the impulse approximation. For the neon atom in the vicinity of the 1s shell ionization threshold our theory predicts the existence of the distinct fine structure of the cross section caused by transitions of the atomic core electrons into the excited discrete spectrum states. The results of our calculations with inclusion of the effects of radial relaxation, inelastic scattering through the intermediate states,more » and elastic Rayleigh scattering, are predictions, while at the 22 keV incident photons they compare well with the synchrotron experiment by Jung et al. [Phys. Rev. Lett. 81, 1596 (1998)].« less

Extreme ultraviolet resonant inelastic X-ray scattering (RIXS) at a seeded free-electron laser

DOE PAGES

Dell’Angela, M.; Hieke, F.; Malvestuto, M.; ...

2016-12-12

In the past few years, we have been witnessing an increased interest for studying materials properties under non-equilibrium conditions. Several well established spectroscopies for experiments in the energy domain have been successfully adapted to the time domain with sub-picosecond time resolution. Here we show the realization of high resolution resonant inelastic X-ray scattering (RIXS) with a stable ultrashort X-ray source such as an externally seeded free electron laser (FEL). We have designed and constructed a RIXS experimental endstation that allowed us to successfully measure the d-d excitations in KCoF 3 single crystals at the cobalt M 2,3-edge at FERMI FELmore » (Elettra-Sincrotrone Trieste, Italy). The FEL-RIXS spectra show an excellent agreement with the ones obtained from the same samples at the MERIXS endstation of the MERLIN beamline at the Advanced Light Source storage ring (Berkeley, USA). We established experimental protocols for performing time resolved RIXS experiments at a FEL source to avoid X ray-induced sample damage, while retaining comparable acquisition time to the synchrotron based measurements. Finally, we measured and modelled the influence of the FEL mixed electromagnetic modes, also present in externally seeded FELs, and the beam transport with ~120 meV experimental resolution achieved in the presented RIXS setup.« less

Resonant inelastic x-ray scattering studies of magnons and bimagnons in the lightly doped cuprate La 2 - x Sr x CuO 4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chaix, L.; Huang, E. W.; Gerber, S.

Here, we investigated the doping dependence of magnetic excitations in the lightly doped cuprate La 2-xSr xCuO 4 via combined studies of resonant inelastic x-ray scattering (RIXS) at the Cu L 3 edge and theoretical calculations. With increasing doping, the magnon dispersion is found to be essentially unchanged, but the spectral width broadens and the spectral weight varies differently at different momenta. Near the Brillouin zone center, we directly observe bimagnon excitations that possess the same energy scale and doping dependence as previously observed by Raman spectroscopy. They disperse weakly in energy-momentum space, and they are consistent with a bimagnonmore » dispersion that is renormalized by the magnon-magnon interaction at the zone center.« less

Resonant inelastic x-ray scattering studies of magnons and bimagnons in the lightly doped cuprate La 2 - x Sr x CuO 4

DOE PAGES

Chaix, L.; Huang, E. W.; Gerber, S.; ...

2018-04-20

Here, we investigated the doping dependence of magnetic excitations in the lightly doped cuprate La 2-xSr xCuO 4 via combined studies of resonant inelastic x-ray scattering (RIXS) at the Cu L 3 edge and theoretical calculations. With increasing doping, the magnon dispersion is found to be essentially unchanged, but the spectral width broadens and the spectral weight varies differently at different momenta. Near the Brillouin zone center, we directly observe bimagnon excitations that possess the same energy scale and doping dependence as previously observed by Raman spectroscopy. They disperse weakly in energy-momentum space, and they are consistent with a bimagnonmore » dispersion that is renormalized by the magnon-magnon interaction at the zone center.« less

Multi-Spectral Solar Telescope Array. II - Soft X-ray/EUV reflectivity of the multilayer mirrors

NASA Technical Reports Server (NTRS)

Barbee, Troy W., Jr.; Weed, J. W.; Hoover, Richard B.; Allen, Maxwell J.; Lindblom, Joakim F.; O'Neal, Ray H.; Kankelborg, Charles C.; Deforest, Craig E.; Paris, Elizabeth S.; Walker, Arthur B. C., Jr.

1991-01-01

The Multispectral Solar Telescope Array is a rocket-borne observatory which encompasses seven compact soft X-ray/EUV, multilayer-coated, and two compact far-UV, interference film-coated, Cassegrain and Ritchey-Chretien telescopes. Extensive measurements are presented on the efficiency and spectral bandpass of the X-ray/EUV telescopes. Attention is given to systematic errors and measurement errors.

High flux table-top ultrafast soft X-ray source generated by high harmonic generation

NASA Astrophysics Data System (ADS)

Thiré, Nicolas; Schmidt, Bruno E.; Fourmeaux, Sylvain; Beaulieu, Samuel; Cardin, Vincent; Negro, Matteo; Kieffer, Jean-Claude; Vozzi, Caterina; Legare, François

2014-05-01

Generation of ultrafast soft X-ray pulses is a major challenge for conventional laboratories. Using the process of HHG enables generation of such short wavelength photons. Intense laser sources in the infrared are necessary to reach the soft X-ray spectral range as the HHG cut-off scales with Iλ2. However, in the limit of the single atom response, increasing the laser wavelength leads to a significant decrease of the HHG flux. To compensate, one has to increase the number of emitters with high ionization potential. At the Advanced Laser Light Source, we have addressed this challenge by using a new gas cell design and developing a 10 mJ - 30 fs source at 1.8 μm. Using this setup, we have been able to generate harmonics in the water window spectral range for neon and helium with short time duration (<30 fs) in a conventional laboratory. A flux measurement has been performed showing ~ 2 × 105 photons/shot between 280 and 540 eV, making it possible to see the carbon k-edge at 280eV in a single shot manner. This soft X-ray beam is also extremely well collimated (0.1 mrad) making it this table-top beamline ideal for a number of applications.

Large area soft x-ray collimator to facilitate x-ray optics testing

NASA Technical Reports Server (NTRS)

Espy, Samuel L.

1994-01-01

The first objective of this program is to design a nested conical foil x-ray optic which will collimate x-rays diverging from a point source. The collimator could then be employed in a small, inexpensive x-ray test stand which would be used to test various x-ray optics and detector systems. The second objective is to demonstrate the fabrication of the x-ray reflectors for this optic using lacquer-smoothing and zero-stress electroforming techniques.

Application of Laser Plasma Sources of Soft X-rays and Extreme Ultraviolet (EUV) in Imaging, Processing Materials and Photoionization Studies

NASA Astrophysics Data System (ADS)

Fiedorowicz, H.; Bartnik, A.; Wachulak, P. W.; Jarocki, R.; Kostecki, J.; Szczurek, M.; Ahad, I. U.; Fok, T.; Szczurek, A.; Wȩgrzyński, Ł.

In the paper we present new applications of laser plasma sources of soft X-rays and extreme ultraviolet (EUV) in various areas of plasma physics, nanotechnology and biomedical engineering. The sources are based on a gas puff target irradiated with nanosecond laser pulses from commercial Nd: YAG lasers, generating pulses with time duration from 1 to 10 ns and energies from 0.5 to 10 J at a 10 Hz repetition rate. The targets are produced with the use of a double valve system equipped with a special nozzle to form a double-stream gas puff target which allows for high conversion efficiency of laser energy into soft X-rays and EUV without degradation of the nozzle. The sources are equipped with various optical systems to collect soft X-ray and EUV radiation and form the radiation beam. New applications of these sources in imaging, including EUV tomography and soft X-ray microscopy, processing of materials and photoionization studies are presented.

Comparison of a CCD and an APS for soft X-ray diffraction

NASA Astrophysics Data System (ADS)

Stewart, Graeme; Bates, R.; Blue, A.; Clark, A.; Dhesi, S. S.; Maneuski, D.; Marchal, J.; Steadman, P.; Tartoni, N.; Turchetta, R.

2011-12-01

We compare a new CMOS Active Pixel Sensor (APS) to a Princeton Instruments PIXIS-XO: 2048B Charge Coupled Device (CCD) with soft X-rays tested in a synchrotron beam line at the Diamond Light Source (DLS). Despite CCDs being established in the field of scientific imaging, APS are an innovative technology that offers advantages over CCDs. These include faster readout, higher operational temperature, in-pixel electronics for advanced image processing and reduced manufacturing cost. The APS employed was the Vanilla sensor designed by the MI3 collaboration and funded by an RCUK Basic technology grant. This sensor has 520 x 520 square pixels, of size 25 μm on each side. The sensor can operate at a full frame readout of up to 20 Hz. The sensor had been back-thinned, to the epitaxial layer. This was the first time that a back-thinned APS had been demonstrated at a beam line at DLS. In the synchrotron experiment soft X-rays with an energy of approximately 708 eV were used to produce a diffraction pattern from a permalloy sample. The pattern was imaged at a range of integration times with both sensors. The CCD had to be operated at a temperature of -55°C whereas the Vanilla was operated over a temperature range from 20°C to -10°C. We show that the APS detector can operate with frame rates up to two hundred times faster than the CCD, without excessive degradation of image quality. The signal to noise of the APS is shown to be the same as that of the CCD at identical integration times and the response is shown to be linear, with no charge blooming effects. The experiment has allowed a direct comparison of back thinned APS and CCDs in a real soft x-ray synchrotron experiment.

Cosmic x ray physics

NASA Technical Reports Server (NTRS)

Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

1990-01-01

The annual progress report on Cosmic X Ray Physics is presented. Topics studied include: the soft x ray background, proportional counter and filter calibrations, the new sounding rocket payload: X Ray Calorimeter, and theoretical studies.

High average power, highly brilliant laser-produced plasma source for soft X-ray spectroscopy.

PubMed

Mantouvalou, Ioanna; Witte, Katharina; Grötzsch, Daniel; Neitzel, Michael; Günther, Sabrina; Baumann, Jonas; Jung, Robert; Stiel, Holger; Kanngiesser, Birgit; Sandner, Wolfgang

2015-03-01

In this work, a novel laser-produced plasma source is presented which delivers pulsed broadband soft X-radiation in the range between 100 and 1200 eV. The source was designed in view of long operating hours, high stability, and cost effectiveness. It relies on a rotating and translating metal target and achieves high stability through an on-line monitoring device using a four quadrant extreme ultraviolet diode in a pinhole camera arrangement. The source can be operated with three different laser pulse durations and various target materials and is equipped with two beamlines for simultaneous experiments. Characterization measurements are presented with special emphasis on the source position and emission stability of the source. As a first application, a near edge X-ray absorption fine structure measurement on a thin polyimide foil shows the potential of the source for soft X-ray spectroscopy.

Soft x-ray emission from solar wind charge exchange in the laboratory

NASA Astrophysics Data System (ADS)

Shimaya, H.; Ishida, T.; Ishikawa, S.; Suda, S.; Tanuma, H.; Akamatsu, H.; Ohashi, H.; Ijima, N.; Inoue, M.; Ezoe, Y.; Ishisaki, Y.; Ohashi, T.; Shinozaki, K.; Mitsuda, K.; Liu, L.; Wang, J.

2013-09-01

We have observed the emission spectra in collisions of bare oxygen ions with a helium gas target in the soft x-ray region with a window-less silicon drift detector at the collision energy range of 48-80 keV. The dominant soft x-ray emission corresponds to the 1s-2p transition of hydrogen-like oxygen O7+ produced by the single-electron charge exchange reaction. Other emission lines are the 1s-3p, 1s-4p and 1s-5p transitions of O7+, and also the 1s2-1s2p transition of O6+ produced by the true double-electron capture. The cascades from the upper states result in a large population of the 2p state, even though the direct capture into the 2p state is extremely scarcer than those into the 3p, 4p and 5p states.

Prospect of space-based interferometry at EUV and soft X-ray wavelengths

NASA Technical Reports Server (NTRS)

Welsh, Barry Y.; Chakrabarti, Supriya

1992-01-01

We review the current capabilities of high-resolution, spectroscopic, space-borne instrumentation available for both solar and stellar observations in the EUV and soft X-ray wavelength regimes, and describe the basic design of a compact, all-reflection interferometer based on the spatial heterodyne technique; this is capable of producing a resolving power (lambda/Delta-lambda) of about 20,000 in the 100-200 A region using presently available multilayer optical components. Such an instrument can be readily constructed with existing technology. Due to its small size and lack of moving parts, it is ideally suited to spaceborne applications. Based on best estimates of the efficiency of this instrument at soft X-ray wavelengths, we review the possible use of this high-resolution interferometer in obtaining high-resolution full-disk spectroscopy of the sun. We also discuss its possible use for observations of diffuse sources such as the EUV interstellar background radiation.

Shot-noise limited throughput of soft x-ray ptychography for nanometrology applications

NASA Astrophysics Data System (ADS)

Koek, Wouter; Florijn, Bastiaan; Bäumer, Stefan; Kruidhof, Rik; Sadeghian, Hamed

2018-03-01

Due to its potential for high resolution and three-dimensional imaging, soft x-ray ptychography has received interest for nanometrology applications. We have analyzed the measurement time per unit area when using soft x-ray ptychography for various nanometrology applications including mask inspection and wafer inspection, and are thus able to predict (order of magnitude) throughput figures. Here we show that for a typical measurement system, using a typical sampling strategy, and when aiming for 10-15 nm resolution, it is expected that a wafer-based topology (2.5D) measurement takes approximately 4 minutes per μm2 , and a full three-dimensional measurement takes roughly 6 hours per μm2 . Due to their much higher reflectivity EUV masks can be measured considerably faster; a measurement speed of 0.1 seconds per μm2 is expected. However, such speeds do not allow for full wafer or mask inspection at industrially relevant throughput.

Condenser optics, partial coherence, and imaging for soft-x-ray projection lithography.

PubMed

Sommargren, G E; Seppala, L G

1993-12-01

A condenser system couples the radiation source to an imaging system, controlling the uniformity and partial coherence at the object, which ultimately affects the characteristics of the aerial image. A soft-x-ray projection lithography system based on a ring-field imaging system and a laser-produced plasma x-ray source places considerable constraints on the design of a condenser system. Two designs are proposed, critical illumination and Köhler illumination, each of which requires three mirrors and scanning for covering the entire ring field with the required uniformity and partial coherence. Images based on Hopkins' formulation of partially coherent imaging are simulated.

Resonant soft x-ray GISAXS on block copolymer films

NASA Astrophysics Data System (ADS)

Wang, Cheng; Araki, T.; Watts, B.; Ade, H.; Hexemer, A.; Park, S.; Russell, T. P.; Schlotter, W. F.; Stein, G. E.; Tang, C.; Kramer, E. J.

2008-03-01

Ordered block copolymer thin films may have important applications in modern device fabrication. Current characterization methods such as conventional GISAXS have fixed electron density contrast that can be overwhelmed by surface scattering. However, soft x-rays have longer wavelength, energy dependent contrast and tunable penetration, making resonant GISAXS a very promising tool for probing nanostructured polymer thin films. Our preliminary investigation was performed using PS-b-P2VP block copolymer films on beam-line 5-2 SSRL, and beam-line 6.3.2 at ALS, LBNL. The contrast/sensitivity of the scattering pattern varies significantly with photon energy close to the C K-edge (˜290 eV). Also, higher order peaks are readily observed, indicating hexagonal packing structure in the sample. Comparing to the hard x-ray GISAXS data of the same system, it is clear that resonant GISAXS has richer data and better resolution. Beyond the results on the A-B diblock copolymers, results on ABC block copolymers are especially interesting.

Structure and collective dynamics of hydrated anti-freeze protein type III from 180 K to 298 K by X-ray diffraction and inelastic X-ray scattering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoshida, Koji; Baron, Alfred Q. R.; Uchiyama, Hiroshi

We investigated hydrated antifreeze protein type III (AFP III) powder with a hydration level h (=mass of water/mass of protein) of 0.4 in the temperature range between 180 K and 298 K using X-ray diffraction and inelastic X-ray scattering (IXS). The X-ray diffraction data showed smooth, largely monotonic changes between 180 K and 298 K without freezing water. Meanwhile, the collective dynamics observed by IXS showed a strong change in the sound velocity at 180 K, after being largely temperature independent at higher temperatures (298–220 K). We interpret this change in terms of the dynamic transition previously discussed using othermore » probes including THz IR absorption spectroscopy and incoherent elastic and quasi-elastic neutron scattering. This finding suggests that the dynamic transition of hydrated proteins is observable on the subpicosecond time scale as well as nano- and pico-second scales, both in collective dynamics from IXS and single particle dynamics from neutron scattering. Moreover, it is most likely that the dynamic transition of hydrated AFP III is not directly correlated with its hydration structure.« less

Soft X-ray observations of pre-main sequence stars in the chamaeleon dark cloud

NASA Technical Reports Server (NTRS)

Feigelson, Eric D.; Kriss, Gerard A.

1987-01-01

Einstein IPC observations of the nearby Chamaeleon I star forming cloud show 22 well-resolved soft X-ray sources in a 1x2 deg region. Twelve are associated with H-alpha emission line pre-main sequence (PMS) stars, and four with optically selected PMS stars. Several X-ray sources have two or more PMS stars in their error circles. Optical spectra were obtained at CTIO of possible stellar counterparts of the remaining X-ray sources. They reveal 5 probable new cloud members, K7-MO stars with weak or absent emission lines. These naked X-ray selected PMS stars are similar to those found in the Taurus-Auriga cloud. The spatial distributions and H-R diagrams of the X-ray and optically selected PMS stars in the cloud are very similar. Luminosity functions indicate the Chamaeleon stars are on average approximately 5 times more X-ray luminous than Pleiad dwarfs. A significant correlation between L sub x and optical magnitude suggests this trend may continue within the PMS phase of stellar evolution. The relation of increasing X-ray luminosity with decreasing stellar ages is thus extended to stellar ages as young as 1 million years.

Cosmic x ray physics

NASA Technical Reports Server (NTRS)

Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

1991-01-01

The annual progress report on Cosmic X Ray Physics for the period 1 Jan. to 31 Dec. 1990 is presented. Topics studied include: soft x ray background, new sounding rocket payload: x ray calorimeter, and theoretical studies.

Soft X-ray emission from the Lupus Loop and Sn 1006 supernova remnants

NASA Technical Reports Server (NTRS)

Winkler, P. F., Jr.; Hearn, D. R.; Richardson, J. A.; Behnken, J. M.

1979-01-01

X-ray maps of the Lupus region have been obtained in a raster scan observation from SAS 3. These show the Lupus Loop to be a faint extended source of soft X-rays with a temperature about 2.5 million K. The most prominent feature of the region is the A.D. 1006 supernova remnant, which is unexpectedly bright at 0.2-1.0 keV. One speculative interpretation of the low-energy flux from SN 1006 is as blackbody radiation from a hot neutron star.

Omega Dante Soft X-Ray Power Diagnostic Component Calibration at the National Synchrotron Light Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campbell, K; Weber, F; Dewald, E

2004-04-15

The Dante soft x-ray spectrometer installed on the Omega laser facility at the Laboratory for Laser Energetics, University of Rochester is a twelve-channel filter-edge defined x-ray power diagnostic. It is used to measure the absolute flux from direct drive, indirect drive (hohlraums) and other plasma sources. Calibration efforts using two beam lines, U3C (50eV-1keV) and X8A (1keV-6keV) at the National Synchrotron Light Source (NSLS) have been implemented to insure the accuracy of these measurements. We have calibrated vacuum x-ray diodes, mirrors and filters.

The discovery and properties of the ultra-soft X-ray transient EXO 1846-031

NASA Technical Reports Server (NTRS)

Parmar, A. N.; Angelini, L.; Roche, P.; White, N. E.

1993-01-01

We report the discovery of a previously uncataloged ultra-soft X-ray transient EXO 1846-031 which was in outburst during 1985 April to September. The X-ray spectrum consists of an ultra-soft component and a high-energy power-law tail that extends to at least 25 keV. The ultra-soft component may be modeled by either a cutoff power-law or a multicolor blackbody disk model. The latter model allows the evolution in spectrum and intensity observed during the outburst to be accounted for by the change in a single parameter - the temperature at the innermost disk radius. We demonstrate that at least one other accretion disk model is able to account for these changes by the variation of a single parameter. During one of the three EXOSAT observations, EXO 1846-031 exhibited significant intensity variability which probably originates from the power-law component. We derive a position for this unidentified source and present the results of a search for the optical counterpart.

Peculiar atomic dynamics in liquid GeTe with asymmetrical bonding: Observation by inelastic x-ray scattering

NASA Astrophysics Data System (ADS)

Inui, M.; Koura, A.; Kajihara, Y.; Hosokawa, S.; Chiba, A.; Kimura, K.; Shimojo, F.; Tsutsui, S.; Baron, A. Q. R.

2018-05-01

Collective dynamics in liquid GeTe was investigated by inelastic x-ray scattering at 2 ≤Q ≤31 nm-1 . The dynamic structure factor shows clear inelastic excitations. The excitation energies at low Q disperse with increasing Q , consistent with the behavior of a longitudinal-acoustic excitation. The dispersion curve has a flat-topped region around the pseudo-Brillouin-zone boundary, similar to what is observed in liquid Bi [Inui et al., Phys. Rev. B 92, 054206 (2015), 10.1103/PhysRevB.92.054206]. The dynamic structure factor shows a low-frequency excitation, and its coupling with the longitudinal-acoustic mode plays an important role for a flat-topped dispersion. From these results, it is inferred that atomic dynamics in liquid GeTe is strongly affected by a Peierls distortion similar to liquid Bi. By comparing the momentum transfer dependence of the excitation energy and quasielastic linewidth to partial structure factors obtained by our own ab initio molecular dynamics simulation for liquid GeTe, the quasielastic and inelastic components were found to be correlated with Te-Te and Ge-(Ge,Te) partial structure factors, respectively.

Contributions of late-type dwarf stars to the soft X-ray diffuse background

NASA Technical Reports Server (NTRS)

Schmitt, J. H. M. M.; Snowden, S. L.

1990-01-01

Comprehensive calculations of the contribution of late-type dwarf stars to the soft X-ray diffuse background are presented. The mean X-ray luminosity as derived from optically and X-ray selected samples is examined, using the Bahcall-Soneira Galaxy model to describe the spatial distribution of stars and recent results on the X-ray spectra. The model calculations are compared with the Wisconsin sky maps in the C, M1, M2, I and J bands to assess the uncertainties of the calculations. Contributions of up to 10 percent to the M2 and I band background at high Galactic latitudes are found, while at low Galactic latitudes late-type stars contribute up to 40 percent of the background. However, a Galactic ridge as well as a relatively isotropic component still remains unexplained, even with the added contribution of the extrapolated high-energy power law.

Apollo-Soyuz survey of the extreme-ultraviolet/soft X-ray background

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stern, R.; Bowyer, S.

1979-06-15

The results of an extensive sky survey of the extreme-ultraviolet (EUV)/soft X-ray background are reported. The data were obtained with a telescope, designed and calibrated at the University of California at Berkeley, which observed EUV sources and the diffuse background as part of the Apollo-Soyuz mission in 1975 July. With a primary field of view of 2 /sup 0/.3 +- 0 /sup 0/.1 FWHM and four EUV bandpass filters (16--25, 20--73, 80--108, and 80--250 eV), the EUV telescope obtained useful background data for 21 sky points, 11 large angle scans, and an additional group of short observations of both types.more » Analysis of the data reveals an intense 80--108 eV diffuse flux of 4.0 +- 1.3 photons cm/sup -2/ sr/sup -1/ eV/sup -1/ (broad-band weighted average). This is roughly a factor of 10 higher than the corresponding 150--280 eV average intensity and confirms the earlier results of Cash, Malina, and Stern. Galactic contributions to the background intensity at still lower energies are most likely masked by large fluxes of geocoronal or interplanetary solar-scattered resonance radiation; however, we drive upper limits to the local galactic background of 2 x 10/sup 4/ and 6 x 10/sup 2/ photons cm/sup -2/ sr/sup -1/ eV/sup -1/ averaged over the 16--25 eV and 20--73 eV bands, respectively. The uniformity of the background flux is uncertain due to limitations in the statistical accuracy of the data; we discuss probable upper limits to any spatial anisotropy. No evidence is found for a correlation between the telescope count rate and Earth-based parameters (zenith angle, Sun angle, etc.) for E> or approx. =80 eV. Unlike some previous claims for the soft X-ray background, no simple dependence upon galactic latitude is seen.Fitting models of thermal emission to the Apollo-Soyuz data yields constraints on model parameters that are consistent for a limited range of temperatures with the EUV results of Cash, Malina, and Stern and the soft X-ray data of Burstein et al.« less

Air kerma calibration factors and chamber correction values for PTW soft x-ray, NACP and Roos ionization chambers at very low x-ray energies.

PubMed

Ipe, N E; Rosser, K E; Moretti, C J; Manning, J W; Palmer, M J

2001-08-01

This paper evaluates the characteristics of ionization chambers for the measurement of absorbed dose to water using very low-energy x-rays. The values of the chamber correction factor, k(ch), used in the IPEMB 1996 code of practice for the UK secondary standard ionization chambers (PTW type M23342 and PTW type M23344), the Roos (PTW type 34001) and NACP electron chambers are derived. The responses in air of the small and large soft x-ray chambers (PTW type M23342 and PTW type M23344) and the NACP and Roos electron ionization chambers were compared. Besides the soft x-ray chambers, the NACP and Roos chambers can be used for very low-energy x-ray dosimetry provided that they are used in the restricted energy range for which their response does not change by more than 5%. The chamber correction factor was found by comparing the absorbed dose to water determined using the dosimetry protocol recommended for low-energy x-rays with that for very low-energy x-rays. The overlap energy range was extended using data from Grosswendt and Knight. Chamber correction factors given in this paper are chamber dependent, varying from 1.037 to 1.066 for a PTW type M23344 chamber, which is very different from a value of unity given in the IPEMB code. However, the values of k(ch) determined in this paper agree with those given in the DIN standard within experimental uncertainty. The authors recommend that the very low-energy section of the IPEMB code is amended to include the most up-to-date values of k(ch).

Yeast cell metabolism investigated by CO{_2} production and soft X-ray irradiation

NASA Astrophysics Data System (ADS)

Masini, A.; Batani, D.; Previdi, F.; Milani, M.; Pozzi, A.; Turcu, E.; Huntington, S.; Takeyasu, H.

1999-01-01

Results obtained using a new technique for studying cell metabolism are presented. The technique, consisting in CO2 production monitoring, has been applied to Saccharomyces cerevisiae yeast cells. Also the cells were irradiated using the soft X-ray laser-plasma source at Rutherford Appleton Laboratory with the aim of producing a damage of metabolic processes at the wall level, responsible for fermentation, without great interference with respiration, taking place in mitochondria, and DNA activity. The source was calibrated with PIN diodes and X-ray spectrometers and used Teflon stripes as target, emitting X-rays at about 0.9 keV, with a very low penetration in biological material. X-ray doses delivered to the different cell compartments were calculated following a Lambert-Bouguet-Beer law. Immediately after irradiation, the damage to metabolic activity was measured again by monitoring CO2 production. Results showed a general reduction in gas production by irradiated samples, together with non-linear and non-monotone response to dose. There was also evidence of oscillations in cell metabolic activity and of X-ray induced changes in oscillation frequency.

The soft X-ray diffuse background observed with the HEAO 1 low-energy detectors

NASA Technical Reports Server (NTRS)

Garmire, G. P.; Nousek, J. A.; Apparao, K. M. V.; Burrows, D. N.; Fink, R. L.; Kraft, R. P.

1992-01-01

Results of a study of the diffuse soft-X-ray background as observed by the low-energy detectors of the A-2 experiment aboard the HEAO 1 satellite are reported. The observed sky intensities are presented as maps of the diffuse X-ray background sky in several energy bands covering the energy range 0.15-2.8 keV. It is found that the soft X-ray diffuse background (SXDB) between 1.5 and 2.8 keV, assuming a power law form with photon number index 1.4, has a normalization constant of 10.5 +/- 1.0 photons/sq cm s sr keV. Below 1.5 keV the spectrum of the SXDB exceeds the extrapolation of this power law. The low-energy excess for the NEP can be fitted with emission from a two-temperature equilibrium plasma model with the temperatures given by log I1 = 6.16 and log T2 = 6.33. It is found that this model is able to account for the spectrum below 1 keV, but fails to yield the observed Galactic latitude variation.

The Miniature X-ray Solar Spectrometer (MinXSS) CubeSats: New soft X-ray spectrometer to investigate properties of hot plasma in the quiet Sun, active regions, and flares.

NASA Astrophysics Data System (ADS)

Moore, C. S.; Dennis, B. R.; Woods, T. N.

2017-12-01

Detection of soft X-rays from the Sun provides direct information on coronal plasma at temperatures in excess of 1 MK. The Miniature X-ray Solar Spectrometer (MinXSS) CubeSats provides new spectrally resolved measurements from 0.8 -12 keV. The MinXSS spectral resolving power (R 40 at 5.9 keV) allows plasma abundances to be determined for Fe, Mg, Ni, Ca, Si, S, and Ar. Long-term temporal variations during quiet-Sun times allow active region contributions to be extracted from the full solar flux. The MinXSS 10 second time cadence allows short-term variations of the soft X-ray flux, temperature, and abundances to be determined during flares. The MinXSS spectroscopic observations, combined with the imaging spectroscopy from the Hinode X-ray Telescope (XRT) and the Reuven Ramaty Solar Spectroscopic Imager (RHESSI), hold great potential for advancing our understanding of solar dynamics.

Seeing real-space dynamics of liquid water through inelastic x-ray scattering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iwashita, Takuya; Wu, Bin; Chen, Wei-Ren

Water is ubiquitous on earth, but we know little about the real-space motion of molecules in liquid water. We demonstrate that high-resolution inelastic x-ray scattering measurement over a wide range of momentum and energy transfer makes it possible to probe real-space, real-time dynamics of water molecules through the so-called Van Hove function. Water molecules are found to be strongly correlated in space and time with coupling between the first and second nearest-neighbor molecules. The local dynamic correlation of molecules observed here is crucial to a fundamental understanding of the origin of the physical properties of water, including viscosity. The resultsmore » also suggest that the quantum-mechanical nature of hydrogen bonds could influence its dynamics. Finally, the approach used here offers a powerful experimental method for investigating real-space dynamics of liquids.« less

Seeing real-space dynamics of liquid water through inelastic x-ray scattering

DOE PAGES

Iwashita, Takuya; Wu, Bin; Chen, Wei-Ren; ...

2017-12-22

Water is ubiquitous on earth, but we know little about the real-space motion of molecules in liquid water. We demonstrate that high-resolution inelastic x-ray scattering measurement over a wide range of momentum and energy transfer makes it possible to probe real-space, real-time dynamics of water molecules through the so-called Van Hove function. Water molecules are found to be strongly correlated in space and time with coupling between the first and second nearest-neighbor molecules. The local dynamic correlation of molecules observed here is crucial to a fundamental understanding of the origin of the physical properties of water, including viscosity. The resultsmore » also suggest that the quantum-mechanical nature of hydrogen bonds could influence its dynamics. Finally, the approach used here offers a powerful experimental method for investigating real-space dynamics of liquids.« less

Seeing real-space dynamics of liquid water through inelastic x-ray scattering.

PubMed

Iwashita, Takuya; Wu, Bin; Chen, Wei-Ren; Tsutsui, Satoshi; Baron, Alfred Q R; Egami, Takeshi

2017-12-01

Water is ubiquitous on earth, but we know little about the real-space motion of molecules in liquid water. We demonstrate that high-resolution inelastic x-ray scattering measurement over a wide range of momentum and energy transfer makes it possible to probe real-space, real-time dynamics of water molecules through the so-called Van Hove function. Water molecules are found to be strongly correlated in space and time with coupling between the first and second nearest-neighbor molecules. The local dynamic correlation of molecules observed here is crucial to a fundamental understanding of the origin of the physical properties of water, including viscosity. The results also suggest that the quantum-mechanical nature of hydrogen bonds could influence its dynamics. The approach used here offers a powerful experimental method for investigating real-space dynamics of liquids.

Determine the yield of micronucleated cells in primary human fibroblasts exposed to focused soft X-rays.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kevin M. Prise

This project was a small part of a larger collaborative study headed by Dr Aloke Chatterjee, (Lawrence Berkeley National Laboratory) and including Drs Les Braby, John Ford (Texas A&M) and Kathy Held (MGH Boston), which was developing an integrated theoretical and experimental model of the radiation-induced bystander response. Our part of the study has been to determine the effectiveness of soft X-rays at inducing chromosomal damage under conditions of direct and bystander exposure. The aim was to compare this with the effectiveness of the low energy 60 kV electron microbeam available at Texas A&M. Previous studies have been performed withmore » primary human fibroblasts measuring micronuclei formation to determine the relative yields of direct versus bystander mediated micronuclei formation after cells were individually irradiated utilizing our novel focused soft X-ray microprobe, which is capable of producing localized submicron beams of carbon-K (278 eV) X-rays. Only a brief overview is given here as the study has been published in several papers. Our original hypothesis was to study yields of bystander-induced micronucleated cells in both wild-type and mutant fibroblast from mouse embryo fibroblasts. Difficulties with the level of background micronuclei in the MEFs prevented systematic studies of bystander responses in the laboratories involved in the collaboration. We then performed these studies with AG1522 primary human fibroblast cells using a siRNA approach developed by John Ford at Texas A&M to knock down DNA PKcs in the first instance. Our soft X-ray source has been in routine use for carbon-K X-rays and is now available with Aluminium-K (1.49 keV) and titanium-K (4.5 keV), although the dose-rate from titanium is still too low at present for most experiments, where large numbers of cells need to be exposed. A separately funded project developed a new soft X-ray microprobe which will give much greater flexibility for changing energies and giving high

Optical surface evaluation by soft X-ray scattering

NASA Technical Reports Server (NTRS)

Green, James C.; Finley, David S.; Bowyer, Stuart; Malina, Roger F.

1986-01-01

During the fabrication of the mirrors for the Extreme Ultraviolet Explorer (EUVE), methods for evaluating the surface quality of the optics have been developed. Measurement of soft X-ray scattering profiles allows for the determination of the surface roughness and correlation lengths for highly polished metal surfaces. With this method, the surface parameters for one of the Wolter Schwarzschild type I mirrors that had been fabricated for the EUVE mission have been determined. The techniques employed, the theoretical basis for the method, and the data that had been taken are presented. The measurements show that the best mirrors have a surface roughness of 20A rms or less.

In-orbit performance of the soft X-ray imaging system aboard Hitomi (ASTRO-H)

NASA Astrophysics Data System (ADS)

Nakajima, Hiroshi; Maeda, Yoshitomo; Uchida, Hiroyuki; Tanaka, Takaaki; Tsunemi, Hiroshi; Hayashida, Kiyoshi; Tsuru, Takeshi G.; Dotani, Tadayasu; Nagino, Ryo; Inoue, Shota; Ozaki, Masanobu; Tomida, Hiroshi; Natsukari, Chikara; Ueda, Shutaro; Mori, Koji; Yamauchi, Makoto; Hatsukade, Isamu; Nishioka, Yusuke; Sakata, Miho; Beppu, Tatsuhiko; Honda, Daigo; Nobukawa, Masayoshi; Hiraga, Junko S.; Kohmura, Takayoshi; Murakami, Hiroshi; Nobukawa, Kumiko K.; Bamba, Aya; Doty, John P.; Iizuka, Ryo; Sato, Toshiki; Kurashima, Sho; Nakaniwa, Nozomi; Asai, Ryota; Ishida, Manadu; Mori, Hideyuki; Soong, Yang; Okajima, Takashi; Serlemitsos, Peter; Tawara, Yuzuru; Mitsuishi, Ikuyuki; Ishibashi, Kazunori; Tamura, Keisuke; Hayashi, Takayuki; Furuzawa, Akihiro; Sugita, Satoshi; Miyazawa, Takuya; Awaki, Hisamitsu; Miller, Eric D.; Yamaguchi, Hiroya

2018-03-01

We describe the in-orbit performance of the soft X-ray imaging system consisting of the Soft X-ray Telescope and the Soft X-ray Imager aboard Hitomi. Verification and calibration of imaging and spectroscopic performance are carried out, making the best use of the limited data of less than three weeks. Basic performance, including a large field of view of {38^' }} × {38^' }}, is verified with the first-light image of the Perseus cluster of galaxies. Amongst the small number of observed targets, the on-minus-off pulse image for the out-of-time events of the Crab pulsar enables us to measure the half-power diameter of the telescope as ˜{1 {^'.} 3}. The average energy resolution measured with the onboard calibration source events at 5.89 keV is 179 ± 3 eV in full width at half maximum. Light leak and crosstalk issues affected the effective exposure time and the effective area, respectively, because all the observations were performed before optimizing an observation schedule and the parameters for the dark-level calculation. Screening the data affected by these two issues, we measure the background level to be 5.6 × 10-6 counts s-1 arcmin-2 cm-2 in the energy band of 5-12 keV, which is seven times lower than that of the Suzaku XIS-BI.

Study of Super- and Subsonic Ionization Fronts in Low-Density, Soft X-Ray-Irradiated Foam Targets

NASA Astrophysics Data System (ADS)

Willi, O.; Barringer, L.; Vickers, C.; Hoarty, D.

2000-04-01

The transition from super- to subsonic propagation of an ionization front has been studied in X-ray irradiated, low-density foam targets using soft X-ray imaging and point projection absorption spectroscopy. The foams were doped with chlorine and irradiated with an intense pulse of soft X-ray radiation with a temperature up to 120 eV produced by laser heating a burnthrough converter foil. The cylindrical foam targets were radiographed side-on allowing the change in the chlorine ionization and hence the front to be observed. From the absolute target transmission the density profile was obtained. Comparison of experimental absorption spectra with simulated ones allowed the temperature of the heated material to be inferred for the first time without reliance on detailed hydrodynamic simulations to interpret the data. The experimental observations were compared to radiation hydrodynamic simulations.

Study of Cr/Sc-based multilayer reflecting mirrors using soft x-ray reflectivity and standing wave-enhanced x-ray fluorescence

NASA Astrophysics Data System (ADS)

Wu, Meiyi; Burcklen, Catherine; André, Jean-Michel; Guen, Karine Le; Giglia, Angelo; Koshmak, Konstantin; Nannarone, Stefano; Bridou, Françoise; Meltchakov, Evgueni; Rossi, Sébastien de; Delmotte, Franck; Jonnard, Philippe

2017-11-01

We study Cr/Sc-based multilayer mirrors designed to work in the water window range using hard and soft x-ray reflectivity as well as x-ray fluorescence enhanced by standing waves. Samples differ by the elemental composition of the stack, the thickness of each layer, and the order of deposition. This paper mainly consists of two parts. In the first part, the optical performances of different Cr/Sc-based multilayers are reported, and in the second part, we extend further the characterization of the structural parameters of the multilayers, which can be extracted by comparing the experimental data with simulations. The methodology is detailed in the case of Cr/B4C/Sc sample for which a three-layer model is used. Structural parameters determined by fitting reflectivity curve are then introduced as fixed parameters to plot the x-ray standing wave curve, to compare with the experiment, and confirm the determined structure of the stack.

Correlative analysis of hard and soft x ray observations of solar flares

NASA Technical Reports Server (NTRS)

Zarro, Dominic M.

1994-01-01

We have developed a promising new technique for jointly analyzing BATSE hard X-ray observations of solar flares with simultaneous soft X-ray observations. The technique is based upon a model in which electric currents and associated electric fields are responsible for the respective heating and particle acceleration that occur in solar flares. A useful by-product of this technique is the strength and evolution of the coronal electric field. The latter permits one to derive important flare parameters such as the current density, the number of current filaments composing the loop, and ultimately the hard X-ray spectrum produced by the runaway electrons. We are continuing to explore the technique by applying it to additional flares for which we have joint BATSE/Yohkoh observations. A central assumption of our analysis is the constant of proportionality alpha relating the hard X-ray flux above 50 keV and the rate of electron acceleration. For a thick-target model of hard X-ray production, it can be shown that cv is in fact related to the spectral index and low-energy cutoff of precipitating electrons. The next step in our analysis is to place observational constraints on the latter parameters using the joint BATSE/Yohkoh data.

Enhancement of soft X-ray lasing action with thin blade radiators

DOEpatents

Suckewer, Szymon; Skinner, Charles H.; Voorhees, David R.

1988-01-01

An enhancement of approximately 100 of stimulated emission over spontaneous emission of the CVI 182 Angstrom line was obtained in a recombining magnetically confined plasma column. The plasma was formed by focusing a CO.sub.2 laser beam on a carbon disc. A magnetic solenoid produced a strong magnetic field which confined the plasma to the shape of a column. A single thin carbon blade extended parallel to the plasma column and served to make the column axially more uniform and also acted as a heat sink. Axial and transverse measurements of the soft X-ray lasing action were made from locations off-set from the central axis of the plasma column. Multiple carbon blades located at equal intervals around the plasma column were also found to produce acceptable results. According to another embodiment 10 a thin coating of aluminum or magnesium was placed on the carbon disc and blade. The Z of the coating should preferably be at least 5 greater than the Z of the target. Measurements of the soft X-rays generated at 182 Angstroms showed a significant increase in intensity enhancement.

Regularization of soft-X-ray imaging in the DIII-D tokamak

DOE PAGES

Wingen, A.; Shafer, M. W.; Unterberg, E. A.; ...

2015-03-02

We developed an image inversion scheme for the soft X-ray imaging system (SXRIS) diagnostic at the DIII-D tokamak in order to obtain the local soft X-ray emission at a poloidal cross-section from the spatially line-integrated image taken by the SXRIS camera. The scheme uses the Tikhonov regularization method since the inversion problem is generally ill-posed. The regularization technique uses the generalized singular value decomposition to determine a solution that depends on a free regularization parameter. The latter has to be chosen carefully, and the so called {\\it L-curve} method to find the optimum regularization parameter is outlined. A representative testmore » image is used to study the properties of the inversion scheme with respect to inversion accuracy, amount/strength of regularization, image noise and image resolution. Moreover, the optimum inversion parameters are identified, while the L-curve method successfully computes the optimum regularization parameter. Noise is found to be the most limiting issue, but sufficient regularization is still possible at noise to signal ratios up to 10%-15%. Finally, the inversion scheme is applied to measured SXRIS data and the line-integrated SXRIS image is successfully inverted.« less

The High Resolution Microcalorimeter Soft X-Ray Spectrometer for the Astro-H Mission

NASA Technical Reports Server (NTRS)

Kelley, Richard L.; Mitsuda, Kazuhisa; den Herder, Jan-Willem A.; Aarts, Henri J. M.; Azzarello, Philipp; Boyce, Kevin R.; Brown, Gregory V.; Chiao, Meng P.; de Vries, Cor P.; DiPirro, Michael J.;

Towards an ab initio theory for metal L-edge soft X-ray spectroscopy of molecular aggregates.

PubMed

Preuße, Marie; Bokarev, Sergey I; Aziz, Saadullah G; Kühn, Oliver

2016-11-01

The Frenkel exciton model was adapted to describe X-ray absorption and resonant inelastic scattering spectra of polynuclear transition metal complexes by means of the restricted active space self-consistent field method. The proposed approach allows to substantially decrease the requirements on computational resources if compared to a full supermolecular quantum chemical treatment. This holds true, in particular, in cases where the dipole approximation to the electronic transition charge density can be applied. The computational protocol was applied to the calculation of X-ray spectra of the hemin complex, which forms dimers in aqueous solution. The aggregation effects were found to be comparable to the spectral alterations due to the replacement of the axial ligand by solvent molecules.

Nuclear resonant inelastic X-ray scattering at high pressure and low temperature

DOE PAGES

Bi, Wenli; Zhao, Jiyong; Lin, Jung -Fu; ...

2015-01-01

In this study, a new synchrotron radiation experimental capability of coupling nuclear resonant inelastic X-ray scattering with the cryogenically cooled high-pressure diamond anvil cell technique is presented. The new technique permits measurements of phonon density of states at low temperature and high pressure simultaneously, and can be applied to studies of phonon contribution to pressure- and temperature-induced magnetic, superconducting and metal–insulator transitions in resonant isotope-bearing materials. In this report, a pnictide sample, EuFe 2As 2, is used as an example to demonstrate this new capability at beamline 3-ID of the Advanced Photon Source, Argonne National Laboratory. A detailed description ofmore » the technical development is given. The Fe-specific phonon density of states and magnetism from the Fe sublattice in Eu 57Fe 2As 2 at high pressure and low temperature were derived by using this new capability.« less

Depth resolved compositional analysis of aluminium oxide thin film using non-destructive soft x-ray reflectivity technique

NASA Astrophysics Data System (ADS)

Sinha, Mangalika; Modi, Mohammed H.

2017-10-01

In-depth compositional analysis of 240 Å thick aluminium oxide thin film has been carried out using soft x-ray reflectivity (SXR) and x-ray photoelectron spectroscopy technique (XPS). The compositional details of the film is estimated by modelling the optical index profile obtained from the SXR measurements over 60-200 Å wavelength region. The SXR measurements are carried out at Indus-1 reflectivity beamline. The method suggests that the principal film region is comprised of Al2O3 and AlOx (x = 1.6) phases whereas the interface region comprised of SiO2 and AlOx (x = 1.6) mixture. The soft x-ray reflectivity technique combined with XPS measurements explains the compositional details of principal layer. Since the interface region cannot be analyzed with the XPS technique in a non-destructive manner in such a case the SXR technique is a powerful tool for nondestructive compositional analysis of interface region.

Refraction effects in soft x-ray multilayer blazed gratings.

PubMed

Voronov, D L; Salmassi, F; Meyer-Ilse, J; Gullikson, E M; Warwick, T; Padmore, H A

2016-05-30

A 2500 lines/mm Multilayer Blazed Grating (MBG) optimized for the soft x-ray wavelength range was fabricated and tested. The grating coated with a W/B₄C multilayer demonstrated a record diffraction efficiency in the 2nd blazed diffraction order in the energy range from 500 to 1200 eV. Detailed investigation of the diffraction properties of the grating demonstrated that the diffraction efficiency of high groove density MBGs is not limited by the normal shadowing effects that limits grazing incidence x-ray grating performance. Refraction effects inherent in asymmetrical Bragg diffraction were experimentally confirmed for MBGs. The refraction affects the blazing properties of the MBGs and results in a shift of the resonance wavelength of the gratings and broadening or narrowing of the grating bandwidth depending on diffraction geometry. The true blaze angle of the MBGs is defined by both the real structure of the multilayer stack and by asymmetrical refraction effects. Refraction effects can be used as a powerful tool in providing highly efficient suppression of high order harmonics.

Evaluating structure in thin block copolymer films with soft x-rays (Conference Presentation)

NASA Astrophysics Data System (ADS)

Sunday, Daniel; Liman, Christopher; Hannon, Adam F.; Ren, Jiaxing; Chen, Xuanxuan; Suh, Hyo Seon; de Pablo, Juan J.; Nealey, Paul F.; Kline, R. Joseph

2017-03-01

The semiconductor industry is evaluating a variety of approaches for the cost efficient production of future processing and memory generations. Amongst the technologies being explored are multiple patterning steps, extreme ultraviolet (EUV) lithography, multiple-beam electron beam lithography and the directed self-assembly (DSA) of block copolymers (BCPs). BCP DSA utilizes a chemical or topographical template to induce long range order in a thin film of BCP which enhances the resolution of the original pattern. The characterization of buried structure within a DSA BCP film is challenging due to the lack of contrast between the organic materials. Critical-dimension small angle x-ray scattering (CDSAXS) measurements were performed on DSA BCP films, using soft X-rays to tune the contrast, in order to understand the relationship between template structure and film morphology.1 The results of these measurements show that as the width of the guiding stripe widens the arrangement of the BCP on the guiding stripe inverts, shifting from the A block being centered on the guiding stripe to the B block being centered on the guiding stripe. The initial results of integration of mean field simulations into the analysis of scattering data will also be discussed. In addition to examining the BCP structure with CDSAXS, soft X-ray reflectivity2 measurements were performed on BCP to better understand the relationship between interface width for systems with alternative architectures (triblocks) and additives (polymers/ionic liquids). The addition of a selectively associating additive increases the interaction parameter between the two blocks, resulting in the reduction of the interface width and access to smaller pitches. The use of soft X-ray reflectivity allows the evaluation of the distribution of the additive. (1) Sunday, D. F.; Hammond, M. R.; Wang, C.; Wu, W.; Delongchamp, D. M.; Tjio, M.; Cheng, J. Y.; Kline, R. J.; Pitera, J. W. Determination of the Internal Morphology of

Imaging mammalian cells with soft x rays: The importance of specimen preparation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, J.T.; Meyer-Ilse, W.

1997-04-01

Studies of mammalian cell structure and spatial organization are a very prominent part of modern cell biology. The interest in them as well as their size make them very accommodating subject specimens for imaging with soft x-rays using the XM-1 transmission microscope built and operated by The Center for X-ray Optics on Beam Line 6.1 at the Advanced Light Source. The purpose of these experiments was to determine if the fixative protocols normally used in electron or visible light microscopy were adequate to allow imaging cells, either fibroblasts or neurons, with minimal visible radiation damage due to imaging with softmore » x-rays at 2.4 nm. Two cell types were selected. Fibroblasts are easily cultured but fragile cells which are commonly used as models for the detailed study of cell physiology. Neurons are complex and sensitive cells which are difficult to prepare and to culture for study in isolation from their connections with surrounding cells. These cell types pose problems in their preparation for any microscopy. To improve the contrast and to prevent postmortem alteration of the chemistry and hence the structure of cells extracted from culture or from living organisms, fixation and staining techniques are employed in electron and visible light microscopy. It has been accepted by biologists for years that these treatments create artifacts and false structure. The authors have begun to develop protocols for specimens of each of these two cell types for soft x-ray microscopy which will preserve them in as near normal state as possible using minimal fixation, and make it possible to image them in either a hydrated or dried state free of secondary addition of stains or other labels.« less

Note: Soft X-ray transmission polarizer based on ferromagnetic thin films

NASA Astrophysics Data System (ADS)

Müller, L.; Hartmann, G.; Schleitzer, S.; Berntsen, M. H.; Walther, M.; Rysov, R.; Roseker, W.; Scholz, F.; Seltmann, J.; Glaser, L.; Viefhaus, J.; Mertens, K.; Bagschik, K.; Frömter, R.; De Fanis, A.; Shevchuk, I.; Medjanik, K.; Öhrwall, G.; Oepen, H. P.; Martins, M.; Meyer, M.; Grübel, G.

2018-03-01

A transmission polarizer for producing elliptically polarized soft X-ray radiation from linearly polarized light is presented. The setup is intended for use at synchrotron and free-electron laser beamlines that do not directly offer circularly polarized light for, e.g., X-ray magnetic circular dichroism (XMCD) measurements or holographic imaging. Here, we investigate the degree of ellipticity upon transmission of linearly polarized radiation through a cobalt thin film. The experiment was performed at a photon energy resonant to the Co L3-edge, i.e., 778 eV, and the polarization of the transmitted radiation was determined using a polarization analyzer that measures the directional dependence of photo electrons emitted from a gas target. Elliptically polarized radiation can be created at any absorption edge showing the XMCD effect by using the respective magnetic element.

A CATALOG OF SOLAR X-RAY PLASMA EJECTIONS OBSERVED BY THE SOFT X-RAY TELESCOPE ON BOARD YOHKOH

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tomczak, M.; Chmielewska, E., E-mail: tomczak@astro.uni.wroc.pl, E-mail: chmielewska@astro.uni.wroc.pl

2012-03-01

A catalog of X-ray plasma ejections (XPEs) observed by the Soft X-ray Telescope on board the Yohkoh satellite has been recently developed in the Astronomical Institute of University of Wroclaw. The catalog contains records of 368 events observed in years 1991-2001 including movies and cross-references to associated events like flares and coronal mass ejections (CMEs). One hundred sixty-three XPEs out of 368 in the catalog were not reported until now. A new classification scheme of XPEs is proposed in which morphology, kinematics, and recurrence are considered. The relation between individual subclasses of XPEs and the associated events was investigated. Themore » results confirm that XPEs are strongly inhomogeneous, responding to different processes that occur in the solar corona. A subclass of erupting loop-like XPEs is a promising candidate to be a high-temperature precursor of CMEs.« less

Hard X-Rays can BE Used to Visualize Cochlear Soft Tissue Displacements in a Closed Cochlea

NASA Astrophysics Data System (ADS)

Richter, C.-P.; Fishman, A.; Fan, L.; Shintani, S.; Rau, C.

2009-02-01

Experiments were made at the Advanced Photon Source (APS), Argonne National Laboratory. The APS is a synchrotron radiation source of the third generation, for which the particular characteristic is the highly coherent X-ray radiation. X-rays are generated with an undulator, inserted in a straight section of the storage ring. Images taken with hard X-rays at full field. A video flow algorithm by Lucas and Kanade was used to determine and quantify cochlear soft tissue displacements. The results show that displacements as low as 100 nm could be visualized.

Arcus: An Overview of the Soft X-ray Grating Explorer

NASA Astrophysics Data System (ADS)

Smith, Randall; Arcus Collaboration

2018-01-01

The Arcus MIDEX Explorer, which NASA selected for a Phase A study in August 2017, provides high-resolution soft X-ray spectroscopy in the 12-50Å bandpass with unprecedented sensitivity. Its capabilities include spectral resolution >2500 and effective areas in the range 200-600 cm^2. The three top science goals for Arcus are (1) to measure the effects of structure formation imprinted upon the hot baryons that are predicted to lie in extended halos around galaxies, groups, and clusters, (2) to trace the propagation of outflowing mass, energy, and momentum from the vicinity of the black hole to extragalactic scales as a measure of their feedback and (3) to explore how stars, circumstellar disks and exoplanet atmospheres form and evolve. Arcus relies upon the same 12m focal length grazing-incidence silicon pore X-ray optics (SPO) that ESA has developed for the Athena mission; the focal length is achieved on orbit via an extendable optical bench. The focused X-rays from these optics are diffracted by high-efficiency Critical-Angle Transmission (CAT) gratings, and the results are imaged with flight-proven CCD detectors and electronics. The power and telemetry requirements on the spacecraft are modest and mission operations are straightforward, as most observations will be long (~100 ksec), uninterrupted, and pre-planned.

Calibration sources and filters of the soft x-ray spectrometer instrument on the Hitomi spacecraft

NASA Astrophysics Data System (ADS)

de Vries, Cor P.; Haas, Daniel; Yamasaki, Noriko Y.; Herder, Jan-Willem den; Paltani, Stephane; Kilbourne, Caroline; Tsujimoto, Masahiro; Eckart, Megan E.; Leutenegger, Maurice A.; Costantini, Elisa; Dercksen, Johannes P. C.; Dubbeldam, Luc; Frericks, Martin; Laubert, Phillip P.; van Loon, Sander; Lowes, Paul; McCalden, Alec J.; Porter, Frederick S.; Ruijter, Jos; Wolfs, Rob

2018-01-01

The soft x-ray spectrometer was designed to operate onboard the Japanese Hitomi (ASTRO-H) satellite. In the beam of this instrument, there was a filter wheel containing x-ray filters and active calibration sources. This paper describes this filter wheel. We show the purpose of the filters and the preflight calibrations performed. In addition, we present the calibration source design and measured performance. Finally, we conclude with prospects for future missions.

Soft X-ray properties of Seyfert galaxies. I - Spectra

NASA Technical Reports Server (NTRS)

Kruper, J. S.; Canizares, C. R.; Urry, C. M.

1990-01-01

Results are presented from a study of soft X-ray spectra of 75 Seyfert galaxies observed by the Einstein Observatory IPC. The spectra in this sample (mostly high-luminosity Seyfert type 1s) are found to be consistent with a single power-law index alpha = 81. The AGN spectra observed with the IPC are compared with those from higher energy experiments, where AGN spectra have power law indices alpha = 0.7. It is found that the IPC spectra are systematically steeper than the HEAO 1 A-2 spectra of the same Seyfert galaxies, indicating a flattening toward higher energies.

Two hump-shaped angular distributions of neutrons and soft X-rays in a small plasma focus device.

PubMed

Habibi, Morteza

2018-03-01

Angular distributions of soft X-rays (SXRs) and neutrons emitted by a small plasma focus device (PFD) were investigated simultaneously using TLD-100 dosimeters and Geiger-Muller activation counters, respectively. The distributions represented two humps with a small dip at the angular position 0° and reduced from the angles of ± 15° and ± 30° for the neutrons and SXRs, respectively. The maximum yield of 2.98 × 10 8 neutrons per shot of the device was obtained at 13.5kV and 6.5mbar. A time of flight (TOF) of 75.2ns between the hard X-ray and the neutron peaks corresponds to neutrons with energy of 2.67MeV. A similar behavior was observed between the angular distributions of neutron and soft X-ray emissions. Copyright © 2018 Elsevier Ltd. All rights reserved.

A color gradient in the soft X-ray diffuse background

NASA Technical Reports Server (NTRS)

Snowden, S. L.; Schmitt, J. H. M. M.; Edwards, B. C.

1990-01-01

It is shown that the deviations of the soft X-ray diffuse background B band to C band intensity ratio from a constant value can be described as a simple dipole-like variation across the sky. In terms of the observed Wisconsin B/C band intensity ratio, the mean value is 0.355, the dipole magnitude is 0.106, and the positive dipole axis points toward l = 168.7 deg, b = 11.2 deg, almost in the galactic anticenter direction. This gradient in the spectral hardness can be due to several causes; the simplest is a temperature gradient in the X-ray emitting plasma of the local cavity from about 10 exp 6.2 K toward the galactic center to about 10 exp 5.9 K in the anticenter direction. While the physical origin of such a temperature gradient is uncertain, the alignment of the dipole with the higher temperature (and absorbed) Loop I region may be significant.

Phonon Lifetime Observation in Epitaxial ScN Film with Inelastic X-Ray Scattering Spectroscopy.

PubMed

Uchiyama, H; Oshima, Y; Patterson, R; Iwamoto, S; Shiomi, J; Shimamura, K

2018-06-08

Phonon-phonon scattering dominates the thermal properties in nonmetallic materials, and it directly influences device performance in applications. The understanding of the scattering has been progressing using computational approaches, and the direct and systematic observation of phonon modes that include momentum dependences is desirable. We report experimental data on the phonon dispersion curves and lifetimes in an epitaxially grown ScN film using inelastic x-ray scattering measurements. The momentum dependence of the optical phonon lifetimes is estimated from the spectral width, and the highest-energy phonon mode around the zone center is found to possess a short lifetime of 0.21 ps. A comparison with first-principles calculations shows that our observed phonon lifetimes are quantitatively explained by three-body phonon-phonon interactions.

Phonon Lifetime Observation in Epitaxial ScN Film with Inelastic X-Ray Scattering Spectroscopy

NASA Astrophysics Data System (ADS)

Uchiyama, H.; Oshima, Y.; Patterson, R.; Iwamoto, S.; Shiomi, J.; Shimamura, K.

2018-06-01

Phonon-phonon scattering dominates the thermal properties in nonmetallic materials, and it directly influences device performance in applications. The understanding of the scattering has been progressing using computational approaches, and the direct and systematic observation of phonon modes that include momentum dependences is desirable. We report experimental data on the phonon dispersion curves and lifetimes in an epitaxially grown ScN film using inelastic x-ray scattering measurements. The momentum dependence of the optical phonon lifetimes is estimated from the spectral width, and the highest-energy phonon mode around the zone center is found to possess a short lifetime of 0.21 ps. A comparison with first-principles calculations shows that our observed phonon lifetimes are quantitatively explained by three-body phonon-phonon interactions.

Prediction and observation of tin and silver plasmas with index of refraction greater than one in the soft x-ray range.

PubMed

Filevich, Jorge; Grava, Jonathan; Purvis, Mike; Marconi, Mario C; Rocca, Jorge J; Nilsen, Joseph; Dunn, James; Johnson, Walter R

2006-07-01

We present the calculated prediction and the experimental confirmation that doubly ionized Ag and Sn plasmas can have an index of refraction greater than one for soft x-ray wavelengths. Interferometry experiments conducted using a capillary discharge soft x-ray laser operating at a wavelength of confirm that in few times ionized laser-created plasmas of these elements the anomalous dispersion from bound electrons can dominate the free electron contribution, making the index of refraction greater than one. The results confirm that bound electrons can strongly influence the index of refraction of numerous plasmas over a broad range of soft x-ray wavelengths confirming recent observations. The understanding of index of refraction at short wavelengths will become even more essential during the next decade as x-ray free electron lasers will become available to probe a wider variety of plasmas at higher densities and shorter wavelengths.

Discovery of soft X-ray flux from 2A 1102+384 = Markarian 421

NASA Technical Reports Server (NTRS)

Hearn, D. R.; Marshall, F. J.; Jernigan, J. G.

1979-01-01

During April 1976 a soft X-ray flux was detected with SAS 3 from the vicinity of 2A 1102+384. The average flux densities were 4.3 x 10 to the -11th and 14 x 10 to the -11th erg/sq cm per sec in the energy bands 0.1-0.28 keV and 1-6 keV, respectively. There is an indication of variability over about 0.5 day in the lowest energy band. An upper limit of 3 x 10 to the 20th H atoms per sq cm is found for the gas column density to the X-ray source. In May 1978, observations with the modulation collimators of SAS 3 yielded an accurate (40 arcsec error radius) position for the X-ray source (2-6 keV) at right ascension 11 h 1 m 39.7 s, declination + 38 deg 28 min 51 sec (equinox 1950). The earlier tentative identification by Ricketts et al. (1976) with the BL Lacertae object B2 1101+38 = Markarian 421 is thus confirmed.

The HEAO-A2 soft X-ray survey of cataclysmic variable stars - EX Hydrae during optical quiescence

NASA Technical Reports Server (NTRS)

Cordova, F. A.; Riegler, G. R.

1979-01-01

Results are reported for HEAO A2 soft X-ray (below 2 keV) scanning observations of the southern dwarf nova EX Hya. An X-ray light curve is presented which shows no apparent orbital modulation. The best-fitting spectral parameters are derived for the source, and the observations are compared with the spectral behavior of the dwarf nova SS Cyg during optical quiescence. The results are discussed in terms of models for X-ray production by accreting white dwarfs.

A new method to calibrate the absolute sensitivity of a soft X-ray streak camera

NASA Astrophysics Data System (ADS)

Yu, Jian; Liu, Shenye; Li, Jin; Yang, Zhiwen; Chen, Ming; Guo, Luting; Yao, Li; Xiao, Shali

2016-12-01

In this paper, we introduce a new method to calibrate the absolute sensitivity of a soft X-ray streak camera (SXRSC). The calibrations are done in the static mode by using a small laser-produced X-ray source. A calibrated X-ray CCD is used as a secondary standard detector to monitor the X-ray source intensity. In addition, two sets of holographic flat-field grating spectrometers are chosen as the spectral discrimination systems of the SXRSC and the X-ray CCD. The absolute sensitivity of the SXRSC is obtained by comparing the signal counts of the SXRSC to the output counts of the X-ray CCD. Results show that the calibrated spectrum covers the range from 200 eV to 1040 eV. The change of the absolute sensitivity in the vicinity of the K-edge of the carbon can also be clearly seen. The experimental values agree with the calculated values to within 29% error. Compared with previous calibration methods, the proposed method has several advantages: a wide spectral range, high accuracy, and simple data processing. Our calibration results can be used to make quantitative X-ray flux measurements in laser fusion research.

Intense Non-Linear Soft X-Ray Emission from a Hydride Target during Pulsed D Bombardment

NASA Astrophysics Data System (ADS)

Miley, George H.; Yang, Yang; Lipson, Andrei; Haque, Munima; Percel, Ian; Romer, Michael

Radiation emission from low-energy nuclear radiation (LENR) electrodes (both charged-particle and X-rays) represents an important feature of LENR in general. Here, calibration, measurement techniques, and soft X-ray emission results from deuterium bombardment of a Pd target (cathode) placed in a pulsed deuterium glow discharge (PGD) are described. An X-ray intensity of 13.4 mW/cm2 and a dose of 3.3 μJ/cm2 were calculated over a 0.5 ms pulse time from AXUV photodiode radiation detector measurements. A most striking feature is that X-ray energies >600 V are observed with a discharge voltage only about half of that value. To further investigate this phenomenon, emission during room temperature D-desorption from electrolytically loaded Pd:Dx cathodes was also studied. The X-ray emission energy observed was quite similar to the PGD case. However, the intensity in this case was almost 13 orders of magnitude lower due to the much lower deuterium fluxes involved.

Probing interfacial characteristics of rubrene/pentacene and pentacene/rubrene bilayers with soft X-ray spectroscopy.

PubMed

Seo, J H; Pedersen, T M; Chang, G S; Moewes, A; Yoo, K-H; Cho, S J; Whang, C N

2007-08-16

The electronic structure of rubrene/pentacene and pentacene/rubrene bilayers has been investigated using soft X-ray absorption spectroscopy, resonant X-ray emission spectroscopy, and density-functional theory calculations. X-ray absorption and emission measurements reveal that it has been possible to alter the lowest unoccupied and the highest occupied molecular orbital states of rubrene in rubrene/pentacene bilayer. In the reverse case, one gets p* molecular orbital states originating from the pentacene layer. Resonant X-ray emission spectra suggest a reduction in the hole-transition probabilities for the pentacene/rubrene bilayer in comparison to reference pentacene layer. For the rubrenepentacene structure, the hole-transition probability shows an increase in comparison to the rubrene reference. We also determined the energy level alignment of the pentacene-rubrene interface by using X-ray and ultraviolet photoelectron spectroscopy. From these comparisons, it is found that the electronic structure of the pentacene-rubrene interface has a strong dependence on interface characteristics which depends on the order of the layers used.

A new method to derive electronegativity from resonant inelastic x-ray scattering.

PubMed

Carniato, S; Journel, L; Guillemin, R; Piancastelli, M N; Stolte, W C; Lindle, D W; Simon, M

2012-10-14

Electronegativity is a well-known property of atoms and substituent groups. Because there is no direct way to measure it, establishing a useful scale for electronegativity often entails correlating it to another chemical parameter; a wide variety of methods have been proposed over the past 80 years to do just that. This work reports a new approach that connects electronegativity to a spectroscopic parameter derived from resonant inelastic x-ray scattering. The new method is demonstrated using a series of chlorine-containing compounds, focusing on the Cl 2p(-1)LUMO(1) electronic states reached after Cl 1s → LUMO core excitation and subsequent KL radiative decay. Based on an electron-density analysis of the LUMOs, the relative weights of the Cl 2p(z) atomic orbital contributing to the Cl 2p(3/2) molecular spin-orbit components are shown to yield a linear electronegativity scale consistent with previous approaches.

A new method to derive electronegativity from resonant inelastic x-ray scattering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carniato, S.; Journel, L.; Guillemin, R.

2012-10-14

Electronegativity is a well-known property of atoms and substituent groups. Because there is no direct way to measure it, establishing a useful scale for electronegativity often entails correlating it to another chemical parameter; a wide variety of methods have been proposed over the past 80 years to do just that. This work reports a new approach that connects electronegativity to a spectroscopic parameter derived from resonant inelastic x-ray scattering. The new method is demonstrated using a series of chlorine-containing compounds, focusing on the Cl 2p{sup -1}LUMO{sup 1} electronic states reached after Cl 1s{yields} LUMO core excitation and subsequent KL radiativemore » decay. Based on an electron-density analysis of the LUMOs, the relative weights of the Cl 2p{sub z} atomic orbital contributing to the Cl 2p{sub 3/2} molecular spin-orbit components are shown to yield a linear electronegativity scale consistent with previous approaches.« less

Bright Linearly and Circularly Polarized Extreme Ultraviolet and Soft X-ray High Harmonics for Absorption Spectroscopy

NASA Astrophysics Data System (ADS)

Fan, Tingting

High harmonic generation (HHG) is an extreme nonlinear optical process. When implemented in a phase-matched geometry, HHG coherent upconverts femtosecond laser light into coherent "X-ray laser" beams, while retaining excellent spatial and temporal coherence, as well as the polarization state of the driving laser. HHG has a tabletop footprint, with femtosecond to attosecond time resolution, combined with nanometer spatial resolution. As a consequence of these unique capabilities, HHG is now being widely adopted for use in molecular spectroscopy and imaging, materials science, as well as nanoimaging in general. In the first half of this thesis, I demonstrate high flux linearly polarized soft X-ray HHG, driven by a single-stage 10-mJ Ti:sapphire regenerative amplifier at a repetition rate of 1 kHz. I first down-converted the laser to 1.3 mum using an optical parametric amplifier, before up-converting it into the soft X-ray region using HHG in a high-pressure, phase-matched, hollow waveguide geometry. The resulting optimally phase-matched broadband spectrum extends to 200 eV, with a soft X-ray photon flux of > 106 photons/pulse/1% bandwidth at 1 kHz, corresponding to > 109 photons/s/1% bandwidth, or approximately a three orders-of-magnitude increase compared with past work. Using this broad bandwidth X-ray source, I demonstrated X-ray absorption spectroscopy of multiple elements and transitions in molecules in a single spectrum, with a spectral resolution of 0.25 eV, and with the ability to resolve the near edge fine structure. In the second half of this thesis, I discuss how to generate the first bright circularly polarized (CP) soft X-ray HHG and also use them to implement the first tabletop X-ray magnetic circular dichroism (XMCD) measurements. Using counter-rotating CP lasers at 1.3 mum and 0.79 mum, I generated CPHHG with photon energies exceeding 160 eV. The harmonic spectra emerge as a sequence of closely spaced pairs of left and right CP peaks, with energies

Bayesian soft X-ray tomography using non-stationary Gaussian Processes

NASA Astrophysics Data System (ADS)

Li, Dong; Svensson, J.; Thomsen, H.; Medina, F.; Werner, A.; Wolf, R.

2013-08-01

In this study, a Bayesian based non-stationary Gaussian Process (GP) method for the inference of soft X-ray emissivity distribution along with its associated uncertainties has been developed. For the investigation of equilibrium condition and fast magnetohydrodynamic behaviors in nuclear fusion plasmas, it is of importance to infer, especially in the plasma center, spatially resolved soft X-ray profiles from a limited number of noisy line integral measurements. For this ill-posed inversion problem, Bayesian probability theory can provide a posterior probability distribution over all possible solutions under given model assumptions. Specifically, the use of a non-stationary GP to model the emission allows the model to adapt to the varying length scales of the underlying diffusion process. In contrast to other conventional methods, the prior regularization is realized in a probability form which enhances the capability of uncertainty analysis, in consequence, scientists who concern the reliability of their results will benefit from it. Under the assumption of normally distributed noise, the posterior distribution evaluated at a discrete number of points becomes a multivariate normal distribution whose mean and covariance are analytically available, making inversions and calculation of uncertainty fast. Additionally, the hyper-parameters embedded in the model assumption can be optimized through a Bayesian Occam's Razor formalism and thereby automatically adjust the model complexity. This method is shown to produce convincing reconstructions and good agreements with independently calculated results from the Maximum Entropy and Equilibrium-Based Iterative Tomography Algorithm methods.

Bayesian soft X-ray tomography using non-stationary Gaussian Processes.

PubMed

Li, Dong; Svensson, J; Thomsen, H; Medina, F; Werner, A; Wolf, R

2013-08-01

In this study, a Bayesian based non-stationary Gaussian Process (GP) method for the inference of soft X-ray emissivity distribution along with its associated uncertainties has been developed. For the investigation of equilibrium condition and fast magnetohydrodynamic behaviors in nuclear fusion plasmas, it is of importance to infer, especially in the plasma center, spatially resolved soft X-ray profiles from a limited number of noisy line integral measurements. For this ill-posed inversion problem, Bayesian probability theory can provide a posterior probability distribution over all possible solutions under given model assumptions. Specifically, the use of a non-stationary GP to model the emission allows the model to adapt to the varying length scales of the underlying diffusion process. In contrast to other conventional methods, the prior regularization is realized in a probability form which enhances the capability of uncertainty analysis, in consequence, scientists who concern the reliability of their results will benefit from it. Under the assumption of normally distributed noise, the posterior distribution evaluated at a discrete number of points becomes a multivariate normal distribution whose mean and covariance are analytically available, making inversions and calculation of uncertainty fast. Additionally, the hyper-parameters embedded in the model assumption can be optimized through a Bayesian Occam's Razor formalism and thereby automatically adjust the model complexity. This method is shown to produce convincing reconstructions and good agreements with independently calculated results from the Maximum Entropy and Equilibrium-Based Iterative Tomography Algorithm methods.

G-133: A soft x ray solar telescope

NASA Technical Reports Server (NTRS)

Williams, Memorie K.; Campbell, Branton; Roming, Peter W. A.; Spute, Mark K.; Moody, J. Ward

1992-01-01

The GOLDHELOX Project, NASA payload number G-133, is a robotic soft x ray solar telescope designed and built by an organization of undergraduate students. The telescope is designed to observe the sun at a wavelength of 171 to 181 A. Since we require observations free from atmospheric interference, the telescope will be launched in a NASA Get-Away-Special (GAS) canister with a Motorized Door Assembly (MDA). In this paper we primarily discuss the most important elements of the telescope itself. We also elaborate on some of the technical difficulties associated with doing good science in space on a small budget (about $100,000) and mention ways in which controlling the instrument environment has reduced the complexity of the system and thus saved us money.

Wide band laser-plasma soft X-ray source using a gas puff target for direct photo-etching of polymers

NASA Astrophysics Data System (ADS)

Bartnik, Andrzej; Fiedorowicz, Henryk; Jarocki, Roman; Kostecki, Jerzy; Rakowski, Rafał; Szczurek, Mirosław

2005-09-01

Organic polymers (PMMA, PTFE, PET, and PI) are considered as the important materials in microengineering, especially for biological and medical applications. Micromachining of such materials is possible with the use of different techniques that involve electromagnetic radiation or charged particle beams. Another possibility of high aspect ratio micromachining of PTFE is direct photo-etching using synchrotron radiation. X-ray and ultraviolet radiation from other sources, for micromachining of materials by direct photo-etching can be also applied. In this paper we present the results of investigation of a wide band soft X-ray source and its application for direct photo-etching of organic polymers. X-ray radiation in the wavelength range from about 3 nm to 20 nm was produced as a result of irradiation of a double-stream gas puff target with laser pulses of energy 0.8 J and time duration of about 3 ns. The spectra, plasma size and absolute energies of soft X-ray pulses for different gas puff targets were measured. Photo-etching process of polymers irradiated with the use of the soft X-ray radiation was analyzed and investigated. Samples of organic polymers were placed inside a vacuum chamber of the x-ray source, close to the gas puff target at the distance of about 2 cm from plasmas created by focused laser pulses. A fine metal grid placed in front of the samples was used as a mask to form structures by x-ray ablation. The results of photo-etching process for several minutes exposition with l0Hz repetition rate were presented. High ablation efficiency was obtained with the use of the gas puff target containing xenon surrounded by helium.